Ian Fisher

All Publications

• Emergent symmetry in TbTe3revealed by ultrafast reflectivity under anisotropic strain. Reports on progress in physics. Physical Society (Great Britain) Kim, S., Orenstein, G., Singh, A., Fisher, I. R., Reis, D., Trigo, M. 2024

  Abstract

  We report ultrafast reflectivity measurements of the dynamics of the order parameter of the charge density wave (CDW) in TbTe3 under anisotropic strain. We observe an increase in the frequency of the amplitude mode with increasing tensile strain along the a-axis (which drives the lattice into a>c, with a and c the lattice constants), and similar behavior for tensile strain along c (c>a). This suggests that both strains stabilize the corresponding CDW order and further support the near equivalence of the CDW phases oriented in the a- and c-axis, in spite of the orthorhombic space group. The results were analyzed within the time-dependent Ginzburg-Landau framework, which agrees well with the reflectivity dynamics. %The strain dependence suggests that the orthogonal a and c CDWs are separately stabilized under the corresponding a > c and c > a strain, respectively. Our study presents an ultrafast approach to assess the stability of phases and order parameter dynamics in strained systems.

  View details for DOI 10.1088/1361-6633/ad71ee

  View details for PubMedID 39168142

• Measurement of the magnetic octupole susceptibility of PrV2Al20. Nature communications Ye, L., Sorensen, M. E., Bachmann, M. D., Fisher, I. R. 2024; 15 (1): 7005

  Abstract

  Revealing the presence of magnetic octupole order and associated octupole fluctuations in solids is a highly challenging task due to the lack of simple external fields that can couple to magnetic octupoles. Here, we demonstrate a methodology for probing the magnetic octupole susceptibility of a candidate material, PrV2Al20, using a product of magnetic field Hi and shear strain ϵjk as a composite effective field, while employing an adiabatic elastocaloric effect to probe the response. We observe Curie-Weiss behavior in the obtained octupolar susceptibility down to approximately 3 K. Although octupole order does not appear to be the leading multipolar channel in PrV2Al20, our results nevertheless reveal the presence of strong magnetic octupole fluctuations and hence demonstrate that octupole order is at least a competing state. More broadly, our results highlight how anisotropic strain can be combined with magnetic fields to probe elusive 'hidden' electronic orders.

  View details for DOI 10.1038/s41467-024-51269-x

  View details for PubMedID 39143053

  View details for PubMedCentralID PMC11325040

• Role of magnetic ions in the thermal Hall effect of the paramagnetic insulator TmVO4 PHYSICAL REVIEW B Vallipuram, A., Chen, L., Campillo, E., Mezidi, M., Grissonnanche, G., Boulanger, M., Lefrancois, E., Zic, M. P., Li, Y., Fisher, I. R., Baglo, J., Taillefer, L. 2024; 110 (4)

  View details for DOI 10.1103/PhysRevB.110.045144

  View details for Web of Science ID 001275928700001

• Anomalous Superfluid Density in a Disordered Charge-Density-Wave Material: Pd-Intercalated ErTe_{3}. Physical review letters Iguchi, Y., Straquadine, J. A., Murthy, C., Kivelson, S. A., Singh, A. G., Fisher, I. R., Moler, K. A. 2024; 133 (3): 036001

  Abstract

  We image local superfluid density in single crystals of Pd-intercalated ErTe_{3} below the superconducting critical temperature T_{c}, well below the onset temperature T_{CDW} of (disordered) charge-density-wave order. We find no detectable inhomogeneities on micron scales. We observe a rapid increase of the superfluid density below T_{c}, deviating from the behavior expected in a conventional Bardeen-Cooper-Schrieffer superconductor, and show that the temperature dependence is qualitatively consistent with a combination of quantum and thermal phase fluctuations.

  View details for DOI 10.1103/PhysRevLett.133.036001

  View details for PubMedID 39094125

• Anomalous Superfluid Density in a Disordered Charge-Density-Wave Material: Pd-Intercalated ErTe₃ PHYSICAL REVIEW LETTERS Iguchi, Y., Straquadine, J. A., Murthy, C., Kivelson, S. A., Singh, A. G., Fisher, I. R., Moler, K. A. 2024; 133 (3)

  View details for DOI 10.1103/PhysRevLett.133.036001

  View details for Web of Science ID 001272200300002

• Giant elastocaloric effect at low temperatures in TmVO4 and implications for cryogenic cooling. Proceedings of the National Academy of Sciences of the United States of America Zic, M. P., Ikeda, M. S., Massat, P., Hollister, P. M., Ye, L., Rosenberg, E. W., Straquadine, J. A., Li, Y., Ramshaw, B. J., Fisher, I. R. 2024; 121 (25): e2320052121

  Abstract

  Adiabatic decompression of paraquadrupolar materials has significant potential as a cryogenic cooling technology. We focus on TmVO[Formula: see text], an archetypal material that undergoes a continuous phase transition to a ferroquadrupole-ordered state at 2.15 K. Above the phase transition, each Tm ion contributes an entropy of [Formula: see text] due to the degeneracy of the crystal electric field groundstate. Owing to the large magnetoelastic coupling, which is a prerequisite for a material to undergo a phase transition via the cooperative Jahn-Teller effect, this level splitting, and hence the entropy, can be readily tuned by externally induced strain. Using a dynamic technique in which the strain is rapidly oscillated, we measure the adiabatic elastocaloric response of single-crystal TmVO[Formula: see text], and thus experimentally obtain the entropy landscape as a function of strain and temperature. The measurement confirms the suitability of this class of materials for cryogenic cooling applications and provides insight into the dynamic quadrupole strain susceptibility.

  View details for DOI 10.1073/pnas.2320052121

  View details for PubMedID 38870056

• Disorder-induced local strain distribution in Y-substituted TmVO₄ PHYSICAL REVIEW B Li, Y., Zic, M. P., Ye, L., Meese, W., Massat, P., Zhu, Y., Fernandes, R. M., Fisher, I. R. 2024; 109 (22)

  View details for DOI 10.1103/PhysRevB.109.224201

  View details for Web of Science ID 001243462800001

• Atomic-scale visualization of a cascade of magnetic orders in the layered antiferromagnet GdTe₃ NPJ QUANTUM MATERIALS Raghavan, A., Romanelli, M., May-Mann, J., Aishwarya, A., Aggarwal, L., Singh, A. G., Bachmann, M. D., Schoop, L. M., Fradkin, E., Fisher, I. R., Madhavan, V. 2024; 9 (1)

  View details for DOI 10.1038/s41535-024-00660-4

  View details for Web of Science ID 001236825300001

• The nematic susceptibility of the ferroquadrupolar metal TmAg₂ measured via the elastocaloric effect NPJ QUANTUM MATERIALS Rosenberg, E. W., Ikeda, M., Fisher, I. R. 2024; 9 (1)

  View details for DOI 10.1038/s41535-024-00658-y

  View details for Web of Science ID 001235303800001

• Emergent tetragonality in a fundamentally orthorhombic material. Science advances Singh, A. G., Bachmann, M. D., Sanchez, J. J., Pandey, A., Kapitulnik, A., Kim, J. W., Ryan, P. J., Kivelson, S. A., Fisher, I. R. 2024; 10 (21): eadk3321

  Abstract

  Symmetry plays a key role in determining the physical properties of materials. By Neumann's principle, the properties of a material remain invariant under the symmetry operations of the space group to which the material belongs. Continuous phase transitions are associated with a spontaneous reduction in symmetry. Less common are examples where proximity to a continuous phase transition leads to an increase in symmetry. We find signatures of an emergent tetragonal symmetry close to a charge density wave (CDW) bicritical point in a fundamentally orthorhombic material, ErTe3, for which the two distinct CDW phase transitions are tuned via anisotropic strain. We first establish that tension along the a axis favors an abrupt rotation of the CDW wave vector from the c to a axis and infer the presence of a bicritical point where the two continuous phase transitions meet. We then observe a divergence of the nematic elastoresistivity approaching this putative bicritical point, indicating an emergent tetragonality in the critical behavior.

  View details for DOI 10.1126/sciadv.adk3321

  View details for PubMedID 38781340

  View details for PubMedCentralID PMC11114214

• Spin Echo, Fidelity, and the Quantum Critical Fan in TmVO4 PHYSICAL REVIEW LETTERS Nian, Y., Vinograd, I., Green, T., Chaffey, C., Massat, P., Singh, R. P., Zic, M. P., Fisher, I. R., Curro, N. J. 2024; 132 (21): 216502

  Abstract

  Using spin-echo nuclear magnetic resonance in the model transverse field Ising system TmVO_{4}, we show that low frequency quantum fluctuations at the quantum critical point have a very different effect on ^{51}V nuclear spins than classical low-frequency noise or fluctuations that arise at a finite temperature critical point. Spin echoes filter out the low-frequency classical noise but not the quantum fluctuations. This allows us to directly visualize the quantum critical fan and demonstrate the persistence of quantum fluctuations at the critical coupling strength in TmVO_{4} to high temperatures in an experiment that remains transparent to finite temperature classical phase transitions. These results show that while dynamical decoupling schemes can be quite effective in eliminating classical noise in a qubit, a quantum critical environment may lead to rapid entanglement and decoherence.

  View details for DOI 10.1103/PhysRevLett.132.216502

  View details for Web of Science ID 001247926000007

  View details for PubMedID 38856271

• Thermal transport measurements through the charge density wave transition in CsV 3 Sb 5 PHYSICAL REVIEW B Kountz, E. D., Murthy, C. R., Chen, D., Ye, L., Zic, M. P., Felser, C., Fisher, I. R., Kivelson, S. A., Kapitulnik, A. 2024; 109 (20)

  View details for DOI 10.1103/PhysRevB.109.L201120

  View details for Web of Science ID 001238169700002

• Vortex phase diagram of the kagome superconductor CsV 3 Sb 5 PHYSICAL REVIEW B Zhang, X., Zic, M. P., Chen, D., Shekhar, C., Felser, C., Fisher, I. R., Kapitulnik, A. 2024; 109 (14)

  View details for DOI 10.1103/PhysRevB.109.144507

  View details for Web of Science ID 001229730300006

• Bragg glass signatures in Pd_<i>x</i>ErTe₃ with X-ray diffraction temperature clustering NATURE PHYSICS Mallayya, K., Straquadine, J., Krogstad, M. J., Bachmann, M. D., Singh, A. G., Osborn, R., Rosenkranz, S., Fisher, I. R., Kim, E. 2024

  View details for DOI 10.1038/s41567-023-02380-1

  View details for Web of Science ID 001160842500001

• Emergent Z2 symmetry near a charge density wave multicritical point PHYSICAL REVIEW B Kivelson, S. A., Pandey, A., Singh, A. G., Kapitulnik, A., Fisher, I. R. 2023; 108 (20)

  View details for DOI 10.1103/PhysRevB.108.205141

  View details for Web of Science ID 001112328100006

• Tensile Microstrain Fluctuations in the BaPbO Units in Superconducting BaPb_1-xBi_xO₃ by Scanning Dispersive Micro-XANES CONDENSED MATTER Albertini, R., Macis, S., Ivanov, A. A., Menushenkov, A. P., Puri, A., Monteseguro, V., Joseph, B., Xu, W., Marcelli, A., Giraldo-Gallo, P., Fisher, I., Bianconi, A., Campi, G. 2023; 8 (3)

  View details for DOI 10.3390/condmat8030057

  View details for Web of Science ID 001073402300001

• Elastocaloric signatures of symmetric and antisymmetric strain-tuning of quadrupolar and magnetic phases in DyB2C2. Proceedings of the National Academy of Sciences of the United States of America Ye, L., Sun, Y., Sunko, V., Rodriguez-Nieva, J. F., Ikeda, M. S., Worasaran, T., Sorensen, M. E., Bachmann, M. D., Orenstein, J., Fisher, I. R. 2023; 120 (35): e2302800120

  Abstract

  The adiabatic elastocaloric effect measures the temperature change of a given system with strain and provides a thermodynamic probe of the entropic landscape in the temperature-strain space. Here, we demonstrate that the DC bias strain-dependence of AC elastocaloric effect allows decomposition of the latter into symmetric (rotation-symmetry-preserving) and antisymmetric (rotation-symmetry-breaking) strain channels, using a tetragonal [Formula: see text]-electron intermetallic DyB[Formula: see text]C[Formula: see text]-whose antiferroquadrupolar order breaks local fourfold rotational symmetries while globally remaining tetragonal-as a showcase example. We capture the strain evolution of its quadrupolar and magnetic phase transitions using both singularities in the elastocaloric coefficient and its jumps at the transitions, and the latter we show follows a modified Ehrenfest relation. We find that antisymmetric strain couples to the underlying order parameter in a biquadratic (linear-quadratic) manner in the antiferroquadrupolar (canted antiferromagnetic) phase, which are attributed to a preserved (broken) global tetragonal symmetry, respectively. The broken tetragonal symmetry in the magnetic phase is further evidenced by elastocaloric strain-hysteresis and optical birefringence. Additionally, within the staggered quadrupolar order, the observed elastocaloric response reflects a quadratic increase of entropy with antisymmetric strain, analogous to the role magnetic field plays for Ising antiferromagnetic orders by promoting pseudospin flips. Our results demonstrate AC elastocaloric effect as a compact and incisive thermodynamic probe into the coupling between electronic degrees of freedom and strain in free energy, which holds the potential for investigating and understanding the symmetry of a wide variety of ordered phases in broader classes of quantum materials.

  View details for DOI 10.1073/pnas.2302800120

  View details for PubMedID 37607225

• Effects of rare-earth magnetism on the superconducting upper critical field in infinite-layer nickelates. Science advances Wang, B. Y., Wang, T. C., Hsu, Y. T., Osada, M., Lee, K., Jia, C., Duffy, C., Li, D., Fowlie, J., Beasley, M. R., Devereaux, T. P., Fisher, I. R., Hussey, N. E., Hwang, H. Y. 2023; 9 (20): eadf6655

  Abstract

  The search for superconductivity in infinite-layer nickelates was motivated by analogy to the cuprates, and this perspective has framed much of the initial consideration of this material. However, a growing number of studies have highlighted the involvement of rare-earth orbitals; in that context, the consequences of varying the rare-earth element in the superconducting nickelates have been much debated. Here, we show notable differences in the magnitude and anisotropy of the superconducting upper critical field across the La-, Pr-, and Nd-nickelates. These distinctions originate from the 4f electron characteristics of the rare-earth ions in the lattice: They are absent for La3+, nonmagnetic for the Pr3+ singlet ground state, and magnetic for the Nd3+ Kramer's doublet. The unique polar and azimuthal angle-dependent magnetoresistance found in the Nd-nickelates can be understood to arise from the magnetic contribution of the Nd3+ 4f moments. Such robust and tunable superconductivity suggests potential in future high-field applications.

  View details for DOI 10.1126/sciadv.adf6655

  View details for PubMedID 37196089

• Nanoscale phase-slip domain walls in the charge density wave state of the Weyl semimetal candidate NbTe4 PHYSICAL REVIEW B Galvis, J. A., Fang, A., Jimenez-Guerrero, D., Rojas-Castillo, J., Casas, J., Herrera, O., Garcia-Castro, A. C., Bousquet, E., Fisher, I. R., Kapitulnik, A., Giraldo-Gallo, P. 2023; 107 (4)

  View details for DOI 10.1103/PhysRevB.107.045120

  View details for Web of Science ID 000922948300010

• Quantum critical fluctuations in an Fe-based superconductor COMMUNICATIONS PHYSICS Jost, D., Peis, L., He, G., Baum, A., Gepraegs, S., Palmstrom, J. C., Ikeda, M. S., Fisher, I. R., Wolf, T., Lederer, S., Kivelson, S. A., Hackl, R. 2022; 5 (1)

  View details for DOI 10.1038/s42005-022-00981-5

  View details for Web of Science ID 000838070600001

• Field-tuned ferroquadrupolar quantum phase transition in the insulator TmVO4. Proceedings of the National Academy of Sciences of the United States of America Massat, P., Wen, J., Jiang, J. M., Hristov, A. T., Liu, Y., Smaha, R. W., Feigelson, R. S., Lee, Y. S., Fernandes, R. M., Fisher, I. R. 2022; 119 (28): e2119942119

  Abstract

  We report results of low-temperature heat-capacity, magnetocaloric-effect, and neutron-diffraction measurements of TmVO4, an insulator that undergoes a continuous ferroquadrupolar phase transition associated with local partially filled 4f orbitals of the thulium (Tm[Formula: see text]) ions. The ferroquadrupolar transition, a realization of Ising nematicity, can be tuned to a quantum critical point by using a magnetic field oriented along the c axis of the tetragonal crystal lattice, which acts as an effective transverse field for the Ising-nematic order. In small magnetic fields, the thermal phase transition can be well described by using a semiclassical mean-field treatment of the transverse-field Ising model. However, in higher magnetic fields, closer to the field-tuned quantum phase transition, subtle deviations from this semiclassical behavior are observed, which are consistent with expectations of quantum fluctuations. Although the phase transition is driven by the local 4f degrees of freedom, the crystal lattice still plays a crucial role, both in terms of mediating the interactions between the local quadrupoles and in determining the critical scaling exponents, even though the phase transition itself can be described via mean field. In particular, bilinear coupling of the nematic order parameter to acoustic phonons changes the spatial and temporal fluctuations of the former in a fundamental way, resulting in different critical behavior of the nematic transverse-field Ising model, as compared to the usual case of the magnetic transverse-field Ising model. Our results establish TmVO4 as a model material and electronic nematicity as a paradigmatic example for quantum criticality in insulators.

  View details for DOI 10.1073/pnas.2119942119

  View details for PubMedID 35787036

• Observation of the non-linear Meissner effect NATURE COMMUNICATIONS Wilcox, J. A., Grant, M. J., Malone, L., Putzke, C., Kaczorowski, D., Wolf, T., Hardy, F., Meingast, C., Analytis, J. G., Chu, J., Fisher, I. R., Carrington, A. 2022; 13 (1): 1201

  Abstract

  A long-standing theoretical prediction is that in clean, nodal unconventional superconductors the magnetic penetration depth λ, at zero temperature, varies linearly with magnetic field. This non-linear Meissner effect is an equally important manifestation of the nodal state as the well studied linear-in-T dependence of λ, but has never been convincingly experimentally observed. Here we present measurements of the nodal superconductors CeCoIn5 and LaFePO which clearly show this non-linear Meissner effect. We further show how the effect of a small dc magnetic field on λ(T) can be used to distinguish gap nodes from non-nodal deep gap minima. Our measurements of KFe2As2 suggest that this material has such a non-nodal state.

  View details for DOI 10.1038/s41467-022-28790-y

  View details for Web of Science ID 000765815800012

  View details for PubMedID 35256611

• Iron pnictides and chalcogenides: a newparadigm for superconductivity. Nature Fernandes, R. M., Coldea, A. I., Ding, H., Fisher, I. R., Hirschfeld, P. J., Kotliar, G. 1800; 601 (7891): 35-44

  Abstract

  Superconductivity is a remarkably widespread phenomenon that is observed in most metals cooled to very low temperatures. The ubiquity of such conventional superconductors, and the wide range of associated critical temperatures, is readily understood in terms of the well-known Bardeen-Cooper-Schrieffer theory. Occasionally, however, unconventional superconductors are found, such as the iron-based materials, which extend and defy this understanding in unexpected ways. In the case of the iron-based superconductors, this includes the different ways in which the presence of multiple atomic orbitals can manifest in unconventional superconductivity, giving rise to a rich landscape of gap structures that share the same dominant pairing mechanism. In addition, these materials have also led to insights into the unusual metallic state governed by the Hund's interaction, the control and mechanisms of electronic nematicity, the impact of magnetic fluctuations and quantum criticality, and the importance of topology in correlated states. Over the fourteen years since their discovery, iron-based superconductors have proven to be a testing ground for the development ofnovel experimental tools and theoretical approaches, both of which have extensively influenced the wider field of quantum materials.

  View details for DOI 10.1038/s41586-021-04073-2

  View details for PubMedID 34987212

• Expanding the momentum field of view in angle-resolved photoemission systems with hemispherical analyzers. The Review of scientific instruments Gauthier, N., Sobota, J. A., Pfau, H., Gauthier, A., Soifer, H., Bachmann, M. D., Fisher, I. R., Shen, Z. X., Kirchmann, P. S. 2021; 92 (12): 123907

  Abstract

  In photoelectron spectroscopy, the measured electron momentum range is intrinsically related to the excitation photon energy. Low photon energies <10 eV are commonly encountered in laser-based photoemission and lead to a momentum range that is smaller than the Brillouin zones of most materials. This can become a limiting factor when studying condensed matter with laser-based photoemission. An additional restriction is introduced by widely used hemispherical analyzers that record only electrons photoemitted in a solid angle set by the aperture size at the analyzer entrance. Here, we present an upgrade to increase the effective solid angle that is measured with a hemispherical analyzer. We achieve this by accelerating the photoelectrons toward the analyzer with an electric field that is generated by a bias voltage on the sample. Our experimental geometry is comparable to a parallel plate capacitor, and therefore, we approximate the electric field to be uniform along the photoelectron trajectory. With this assumption, we developed an analytic, parameter-free model that relates the measured angles to the electron momenta in the solid and verify its validity by comparing with experimental results on the charge density wave material TbTe3. By providing a larger field of view in momentum space, our approach using a bias potential considerably expands the flexibility of laser-based photoemission setups.

  View details for DOI 10.1063/5.0053479

  View details for PubMedID 34972440

• Expanding the momentum field of view in angle-resolved photoemission systems with hemispherical analyzers REVIEW OF SCIENTIFIC INSTRUMENTS Gauthier, N., Sobota, J. A., Pfau, H., Gauthier, A., Soifer, H., Bachmann, M. D., Fisher, I. R., Shen, Z., Kirchmann, P. S. 2021; 92 (12)

  View details for DOI 10.1063/5.0053479

  View details for Web of Science ID 000731435700002

• Role of Equilibrium Fluctuations in Light-Induced Order. Physical review letters Zong, A., Dolgirev, P. E., Kogar, A., Su, Y., Shen, X., Straquadine, J. A., Wang, X., Luo, D., Kozina, M. E., Reid, A. H., Li, R., Yang, J., Weathersby, S. P., Park, S., Sie, E. J., Jarillo-Herrero, P., Fisher, I. R., Wang, X., Demler, E., Gedik, N. 2021; 127 (22): 227401

  Abstract

  Engineering novel states of matter with light is at the forefront of materials research. An intensely studied direction is to realize broken-symmetry phases that are "hidden" under equilibrium conditions but can be unleashed by an ultrashort laser pulse. Despite a plethora of experimental discoveries, the nature of these orders and how they transiently appear remain unclear. To this end, we investigate a nonequilibrium charge density wave (CDW) in rare-earth tritellurides, which is suppressed in equilibrium but emerges after photoexcitation. Using a pump-pump-probe protocol implemented in ultrafast electron diffraction, we demonstrate that the light-induced CDW consists solely of order parameter fluctuations, which bear striking similarities to critical fluctuations in equilibrium despite differences in the length scale. By calculating the dynamics of CDW fluctuations in a nonperturbative model, we further show that the strength of the light-induced order is governed by the amplitude of equilibrium fluctuations. These findings highlight photoinduced fluctuations as an important ingredient for the emergence of transient orders out of equilibrium. Our results further suggest that materials with strong fluctuations in equilibrium are promising platforms to host hidden orders after laser excitation.

  View details for DOI 10.1103/PhysRevLett.127.227401

  View details for PubMedID 34889631

• Role of Equilibrium Fluctuations in Light-Induced Order PHYSICAL REVIEW LETTERS Zong, A., Dolgirev, P. E., Kogar, A., Su, Y., Shen, X., Straquadine, J. W., Wang, X., Luo, D., Kozina, M. E., Reid, A. H., Li, R., Yang, J., Weathersby, S. P., Park, S., Sie, E. J., Jarillo-Herrero, P., Fisher, I. R., Wang, X., Demler, E., Gedik, N. 2021; 127 (22)

  View details for DOI 10.1103/PhysRevLett.127.227401

  View details for Web of Science ID 000723128100004

• Elastocaloric signature of nematic fluctuations. Proceedings of the National Academy of Sciences of the United States of America Ikeda, M. S., Worasaran, T., Rosenberg, E. W., Palmstrom, J. C., Kivelson, S. A., Fisher, I. R. 2021; 118 (37)

  Abstract

  The elastocaloric effect (ECE) relates changes in entropy to changes in strain experienced by a material. As such, ECE measurements can provide valuable information about the entropy landscape proximate to strain-tuned phase transitions. For ordered states that break only point symmetries, bilinear coupling of the order parameter with strain implies that the ECE can also provide a window on fluctuations above the critical temperature and hence, in principle, can also provide a thermodynamic measure of the associated susceptibility. To demonstrate this, we use the ECE to sensitively reveal the presence of nematic fluctuations in the archetypal Fe-based superconductor Ba([Formula: see text])2[Formula: see text] By performing these measurements simultaneously with elastoresistivity in a multimodal fashion, we are able to make a direct and unambiguous comparison of these closely related thermodynamic and transport properties, both of which are sensitive to nematic fluctuations. As a result, we have uncovered an unanticipated doping dependence of the nemato-elastic coupling and of the magnitude of the scattering of low-energy quasi-particles by nematic fluctuations-while the former weakens, the latter increases dramatically with increasing doping.

  View details for DOI 10.1073/pnas.2105911118

  View details for PubMedID 34503998

• Anderson localization of electron states in a quasicrystal PHYSICAL REVIEW B Sarkar, S., Krajci, M., Sadhukhan, P., Singh, V., Gloskovskii, A., Mandal, P., Fournee, V., de Weerd, M., Ledieu, J., Fisher, I. R., Barman, S. 2021; 103 (24)

  View details for DOI 10.1103/PhysRevB.103.L241106

  View details for Web of Science ID 000661523400004

• Signatures of two-dimensional superconductivity emerging within a three-dimensional host superconductor. Proceedings of the National Academy of Sciences of the United States of America Parra, C., Niestemski, F. C., Contryman, A. W., Giraldo-Gallo, P., Geballe, T. H., Fisher, I. R., Manoharan, H. C. 2021; 118 (16)

  Abstract

  Spatial disorder has been shown to drive two-dimensional (2D) superconductors to an insulating phase through a superconductor-insulator transition (SIT). Numerical calculations predict that with increasing disorder, emergent electronic granularity is expected in these materials-a phenomenon where superconducting (SC) domains on the scale of the material's coherence length are embedded in an insulating matrix and coherently coupled by Josephson tunneling. Here, we present spatially resolved scanning tunneling spectroscopy (STS) measurements of the three-dimensional (3D) superconductor BaPb1-x Bi x O3 (BPBO), which surprisingly demonstrate three key signatures of emergent electronic granularity, having only been previously conjectured and observed in 2D thin-film systems. These signatures include the observation of emergent SC domains on the scale of the coherence length, finite energy gap over all space, and strong enhancement of spatial anticorrelation between pairing amplitude and gap magnitude as the SIT is approached. These observations are suggestive of 2D SC behavior embedded within a conventional 3D s-wave host, an intriguing but still unexplained interdimensional phenomenon, which has been hinted at by previous experiments in which critical scaling exponents in the vicinity of a putative 3D quantum phase transition are consistent only with dimensionality d = 2.

  View details for DOI 10.1073/pnas.2017810118

  View details for PubMedID 33846248

• Nematic quantum criticality in an Fe-based superconductor revealed by strain-tuning. Science (New York, N.Y.) Worasaran, T., Ikeda, M. S., Palmstrom, J. C., Straquadine, J. A., Kivelson, S. A., Fisher, I. R. 2021; 372 (6545): 973-977

  Abstract

  Quantum criticality may be essential to understanding a wide range of exotic electronic behavior; however, conclusive evidence of quantum critical fluctuations has been elusive in many materials of current interest. An expected characteristic feature of quantum criticality is power-law behavior of thermodynamic quantities as a function of a nonthermal tuning parameter close to the quantum critical point (QCP). Here, we observed power-law behavior of the critical temperature of the coupled nematic/structural phase transition as a function of uniaxial stress in a representative family of iron-based superconductors, providing direct evidence of quantum critical nematic fluctuations in this material. These quantum critical fluctuations are not confined within a narrow regime around the QCP but rather extend over a wide range of temperatures and compositions.

  View details for DOI 10.1126/science.abb9280

  View details for PubMedID 34045352

• Robust superconductivity intertwined with charge density wave and disorder in Pd-intercalated ErTe3 PHYSICAL REVIEW RESEARCH Fang, A., Singh, A. G., Straquadine, J. W., Fisher, I. R., Kivelson, S. A., Kapitulnik, A. 2020; 2 (4)

  View details for DOI 10.1103/PhysRevResearch.2.043221

  View details for Web of Science ID 000605409000004

• Interplay of charge density wave states and strain at the surface of CeTe2 PHYSICAL REVIEW B Sharma, B., Singh, M., Ahmed, B., Yu, B., Walmsley, P., Fisher, I. R., Boyer, M. C. 2020; 101 (24)

  View details for DOI 10.1103/PhysRevB.101.245423

  View details for Web of Science ID 000540656500004

• High resolution time- and angle-resolved photoemission spectroscopy with 11 eV laser pulses. The Review of scientific instruments Lee, C., Rohwer, T., Sie, E. J., Zong, A., Baldini, E., Straquadine, J., Walmsley, P., Gardner, D., Lee, Y. S., Fisher, I. R., Gedik, N. 2020; 91 (4): 043102

  Abstract

  Performing time- and angle-resolved photoemission (tr-ARPES) spectroscopy at high momenta necessitates extreme ultraviolet laser pulses, which are typically produced via high harmonic generation (HHG). Despite recent advances, HHG-based setups still require large pulse energies (from hundreds of μJ to mJ) and their energy resolution is limited to tens of meV. Here, we present a novel 11 eV tr-ARPES setup that generates a flux of 5 × 1010 photons/s and achieves an unprecedented energy resolution of 16 meV. It can be operated at high repetition rates (up to 250 kHz) while using input pulse energies down to 3 µJ. We demonstrate these unique capabilities by simultaneously capturing the energy and momentum resolved dynamics in two well-separated momentum space regions of a charge density wave material ErTe3. This novel setup offers the opportunity to study the non-equilibrium band structure of solids with exceptional energy and time resolutions at high repetition rates.

  View details for DOI 10.1063/1.5139556

  View details for PubMedID 32357712

• High resolution time- and angle-resolved photoemission spectroscopy with 11 eV laser pulses REVIEW OF SCIENTIFIC INSTRUMENTS Lee, C., Rohwer, T., Sie, E. J., Zong, A., Baldini, E., Straquadine, J., Walmsley, P., Gardner, D., Lee, Y. S., Fisher, I. R., Gedik, N. 2020; 91 (4)

  View details for DOI 10.1063/1.5139556

  View details for Web of Science ID 000526759500002

• Nematic transitions in iron pnictide superconductors imaged with a quantum gas NATURE PHYSICS Yang, F., Taylor, S. F., Edkins, S. D., Palmstrom, J. C., Fisher, I. R., Lev, B. L. 2020

  View details for DOI 10.1038/s41567-020-0826-8

  View details for Web of Science ID 000522383200001

• Light-induced charge density wave in LaTe3 NATURE PHYSICS Kogar, A., Zong, A., Dolgirev, P. E., Shen, X., Straquadine, J., Bie, Y., Wang, X., Rohwer, T., Tung, I., Yang, Y., Li, R., Yang, J., Weathersby, S., Park, S., Kozina, M. E., Sie, E. J., Wen, H., Jarillo-Herrero, P., Fisher, I. R., Wang, X., Gedik, N. 2020; 16 (2): 159-+

  View details for DOI 10.1038/s41567-019-0705-3

  View details for Web of Science ID 000511518200012

• Disorder-induced suppression of charge density wave order: STM study of Pd-intercalated ErTe3 PHYSICAL REVIEW B Fang, A., Straquadine, J. W., Fisher, I. R., Kivelson, S. A., Kapitulnik, A. 2019; 100 (23)

  View details for DOI 10.1103/PhysRevB.100.235446

  View details for Web of Science ID 000504445200004

• Dynamical Slowing-Down in an Ultrafast Photoinduced Phase Transition. Physical review letters Zong, A., Dolgirev, P. E., Kogar, A., Ergeçen, E., Yilmaz, M. B., Bie, Y. Q., Rohwer, T., Tung, I. C., Straquadine, J., Wang, X., Yang, Y., Shen, X., Li, R., Yang, J., Park, S., Hoffmann, M. C., Ofori-Okai, B. K., Kozina, M. E., Wen, H., Wang, X., Fisher, I. R., Jarillo-Herrero, P., Gedik, N. 2019; 123 (9): 097601

  Abstract

  Complex systems, which consist of a large number of interacting constituents, often exhibit universal behavior near a phase transition. A slowdown of certain dynamical observables is one such recurring feature found in a vast array of contexts. This phenomenon, known as critical slowing-down, is well studied mostly in thermodynamic phase transitions. However, it is less understood in highly nonequilibrium settings, where the time it takes to traverse the phase boundary becomes comparable to the timescale of dynamical fluctuations. Using transient optical spectroscopy and femtosecond electron diffraction, we studied a photoinduced transition of a model charge-density-wave (CDW) compound LaTe_{3}. We observed that it takes the longest time to suppress the order parameter at the threshold photoexcitation density, where the CDW transiently vanishes. This finding can be captured by generalizing the time-dependent Landau theory to a system far from equilibrium. The experimental observation and theoretical understanding of dynamical slowing-down may offer insight into other general principles behind nonequilibrium phase transitions in many-body systems.

  View details for DOI 10.1103/PhysRevLett.123.097601

  View details for PubMedID 31524450

• Dynamical Slowing-Down in an Ultrafast Photoinduced Phase Transition PHYSICAL REVIEW LETTERS Zong, A., Dolgirev, P. E., Kogar, A., Ergecen, E., Yilmaz, M. B., Bie, Y., Rohwer, T., Tung, I., Straquadine, J., Wang, X., Yang, Y., Shen, X., Li, R., Yang, J., Park, S., Hoffmann, M. C., Ofori-Okai, B. K., Kozina, M. E., Wen, H., Wang, X., Fisher, I. R., Jarillo-Herrero, P., Gedik, N. 2019; 123 (9)

  View details for DOI 10.1103/PhysRevLett.123.097601

  View details for Web of Science ID 000483048500015

• Imaging anisotropic vortex dynamics in FeSe PHYSICAL REVIEW B Zhang, I. P., Palmstrom, J. C., Noad, H., Bishop-Van Horn, L., Iguchi, Y., Cui, Z., Mueller, E., Kirtley, J. R., Fisher, I. R., Moler, K. A. 2019; 100 (2)

  View details for DOI 10.1103/PhysRevB.100.024514

  View details for Web of Science ID 000476686700006

• Phase transition preceding magnetic long-range order in the double perovskite Ba2NaOsO6 PHYSICAL REVIEW B Willa, K., Willa, R., Welp, U., Fisher, I. R., Rydh, A., Kwok, W., Islam, Z. 2019; 100 (4)

  View details for DOI 10.1103/PhysRevB.100.041108

  View details for Web of Science ID 000475500000001

• Divergence of the quadrupole-strain susceptibility of the electronic nematic system YbRu2Ge2 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Rosenberg, E. W., Chu, J., Ruff, J. C., Hristov, A. T., Fisher, I. R. 2019; 116 (15): 7232–37

  View details for DOI 10.1073/pnas.1818910116

  View details for Web of Science ID 000463936900017

• Elastoresistive and elastocaloric anomalies at magnetic and electronic-nematic critical points PHYSICAL REVIEW B Hristov, A. T., Ikeda, M. S., Palmstrom, J. C., Walmsley, P., Fisher, I. R. 2019; 99 (10)

  View details for DOI 10.1103/PhysRevB.99.100101

  View details for Web of Science ID 000460720900001

• Multi-band mass enhancement towards critical doping in a pnictide superconductor NPJ QUANTUM MATERIALS Moir, C., Riggs, S., Galvis, J., Lian, X., Giraldo-Gallo, P., Chu, J., Walmsley, P., Fisher, I., Shekhter, A., Boebinger, G. 2019; 4

  View details for DOI 10.1038/s41535-018-0144-x

  View details for Web of Science ID 000470238000001

• Optical anisotropy in optimally doped iron-based superconductor NPJ QUANTUM MATERIALS Pal, A., Chinotti, M., Chu, J., Kuo, H., Fisher, I., Degiorgi, L. 2019; 4

  View details for DOI 10.1038/s41535-018-0140-1

  View details for Web of Science ID 000470236600001

• Evidence for topological defects in a photoinduced phase transition NATURE PHYSICS Zong, A., Kogar, A., Bie, Y., Rohwer, T., Lee, C., Baldini, E., Ergecen, E., Yilmaz, M. B., Freelon, B., Sie, E. J., Zhou, H., Straquadine, J., Walmsley, P., Dolgirev, P. E., Rozhkov, A. V., Fisher, I. R., Jarillo-Herrero, P., Fine, B. V., Gedik, N. 2019; 15 (1): 27-+

  View details for DOI 10.1038/s41567-018-0311-9

  View details for Web of Science ID 000454733100015

• Combining time-resolved optical (TOS), electronic (trARPES) and structural (UED) probes on the class of rare earth tritellurides RTe3 Rohwero, T., Zong, A., Kogar, A., Bie, Y., Lee, C., Baldini, E., Ergecen, E., Yilmaz, M. B., Freelon, B., Sie, E. J., Zhou, H., Straquadine, J., Walmsley, P., Dolgirev, P. E., Rozhkov, A., Fisher, I. R., Jarillo-Herrero, P., Fine, B., Gedik, N., Cerullo, G., Ogilvie, J., Kartner, F., Khalil, M., Li, R. E D P SCIENCES. 2019

  View details for DOI 10.1051/epjconf/201920504009

  View details for Web of Science ID 000570451400078

• Measurement of elastoresistivity at finite frequency by amplitude demodulation. The Review of scientific instruments Hristov, A. T., Palmstrom, J. C., Straquadine, J. A., Merz, T. A., Hwang, H. Y., Fisher, I. R. 2018; 89 (10): 103901

  Abstract

  Elastoresistivity, the relation between resistivity and strain, can elucidate the subtle properties of the electronic structure of a material and is an increasingly important tool for the study of strongly correlated materials. To date, elastoresistivity measurements have predominantly been performed with quasi-static (DC) strain. In this work, we demonstrate a method using AC strain in elastoresistivity measurements. A sample experiencing AC strain has a time-dependent resistivity, which modulates the voltage produced by an AC current; this effect produces time-dependent variations in resistivity that are directly proportional to the elastoresistivity, and which can be measured more quickly, with less strain on the sample, and with less stringent requirements for temperature stability than the previous DC technique. Example measurements between 10 Hz and 3 kHz are performed on a material with a large, well-characterized and temperature dependent elastoresistivity: the representative iron-based superconductor Ba(Fe0.975Co0.025)2As2. These measurements yield a frequency independent elastoresistivity and reproduce results from previous DC elastoresistivity methods to within experimental accuracy. We emphasize that the dynamic (AC) elastoresistivity is a distinct material-specific property that has not previously been considered.

  View details for PubMedID 30399873

• Anomalous Te-125 Nuclear Spin Relaxation Coincident with Charge Kondo Behavior in Superconducting Pb1-xTlxTe JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN Mukuda, H., Matsumura, T., Maki, S., Yashima, M., Kitaoka, Y., Miyake, K., Murakami, H., Giraldo-Gallo, P., Geball, T. H., Fisher, I. R. 2018; 87 (2)

  View details for DOI 10.7566/JPSJ.87.023706

  View details for Web of Science ID 000423790900001

• Transverse fields to tune an Ising-nematic quantum phase transition PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Maharaj, A. V., Rosenberg, E. W., Hristov, A. T., Berg, E., Fernandes, R. M., Fisher, I. R., Kivelson, S. A. 2017; 114 (51): 13430–34

  Abstract

  The paradigmatic example of a continuous quantum phase transition is the transverse field Ising ferromagnet. In contrast to classical critical systems, whose properties depend only on symmetry and the dimension of space, the nature of a quantum phase transition also depends on the dynamics. In the transverse field Ising model, the order parameter is not conserved, and increasing the transverse field enhances quantum fluctuations until they become strong enough to restore the symmetry of the ground state. Ising pseudospins can represent the order parameter of any system with a twofold degenerate broken-symmetry phase, including electronic nematic order associated with spontaneous point-group symmetry breaking. Here, we show for the representative example of orbital-nematic ordering of a non-Kramers doublet that an orthogonal strain or a perpendicular magnetic field plays the role of the transverse field, thereby providing a practical route for tuning appropriate materials to a quantum critical point. While the transverse fields are conjugate to seemingly unrelated order parameters, their nontrivial commutation relations with the nematic order parameter, which can be represented by a Berry-phase term in an effective field theory, intrinsically intertwine the different order parameters.

  View details for PubMedID 29208710

• Tuning Perpendicular Magnetic Anisotropy by Oxygen Octahedral Rotations in (La_{1-x}Sr_{x}MnO_{3})/(SrIrO_{3}) Superlattices. Physical review letters Yi, D., Flint, C. L., Balakrishnan, P. P., Mahalingam, K., Urwin, B., Vailionis, A., N'Diaye, A. T., Shafer, P., Arenholz, E., Choi, Y., Stone, K. H., Chu, J. H., Howe, B. M., Liu, J., Fisher, I. R., Suzuki, Y. 2017; 119 (7): 077201

  Abstract

  Perpendicular magnetic anisotropy (PMA) plays a critical role in the development of spintronics, thereby demanding new strategies to control PMA. Here we demonstrate a conceptually new type of interface induced PMA that is controlled by oxygen octahedral rotation. In superlattices comprised of La_{1-x}Sr_{x}MnO_{3} and SrIrO_{3}, we find that all superlattices (0≤x≤1) exhibit ferromagnetism despite the fact that La_{1-x}Sr_{x}MnO_{3} is antiferromagnetic for x>0.5. PMA as high as 4×10^{6}  erg/cm^{3} is observed by increasing x and attributed to a decrease of oxygen octahedral rotation at interfaces. We also demonstrate that oxygen octahedral deformation cannot explain the trend in PMA. These results reveal a new degree of freedom to control PMA, enabling discovery of emergent magnetic textures and topological phenomena.

  View details for DOI 10.1103/PhysRevLett.119.077201

  View details for PubMedID 28949659

• HfSe2 and ZrSe2: Two-dimensional semiconductors with native high-κ oxides. Science advances Mleczko, M. J., Zhang, C., Lee, H. R., Kuo, H. H., Magyari-Köpe, B., Moore, R. G., Shen, Z. X., Fisher, I. R., Nishi, Y., Pop, E. 2017; 3 (8): e1700481

  Abstract

  The success of silicon as a dominant semiconductor technology has been enabled by its moderate band gap (1.1 eV), permitting low-voltage operation at reduced leakage current, and the existence of SiO2 as a high-quality "native" insulator. In contrast, other mainstream semiconductors lack stable oxides and must rely on deposited insulators, presenting numerous compatibility challenges. We demonstrate that layered two-dimensional (2D) semiconductors HfSe2 and ZrSe2 have band gaps of 0.9 to 1.2 eV (bulk to monolayer) and technologically desirable "high-κ" native dielectrics HfO2 and ZrO2, respectively. We use spectroscopic and computational studies to elucidate their electronic band structure and then fabricate air-stable transistors down to three-layer thickness with careful processing and dielectric encapsulation. Electronic measurements reveal promising performance (on/off ratio > 106; on current, ~30 μA/μm), with native oxides reducing the effects of interfacial traps. These are the first 2D materials to demonstrate technologically relevant properties of silicon, in addition to unique compatibility with high-κ dielectrics, and scaling benefits from their atomically thin nature.

  View details for DOI 10.1126/sciadv.1700481

  View details for PubMedID 28819644

  View details for PubMedCentralID PMC5553816

• Determination of the resistivity anisotropy of orthorhombic materials via transverse resistivity measurements REVIEW OF SCIENTIFIC INSTRUMENTS Walmsley, P., Fisher, I. R. 2017; 88 (4)

  Abstract

  Measurements of the resistivity anisotropy can provide crucial information about the electronic structure and scattering processes in anisotropic and low-dimensional materials, but quantitative measurements by conventional means often suffer very significant systematic errors. Here we describe a novel approach to measuring the resistivity anisotropy of orthorhombic materials, using a single crystal and a single measurement that is derived from a π4 rotation of the measurement frame relative to the crystallographic axes. In this new basis, the transverse resistivity gives a direct measurement of the resistivity anisotropy, which combined with the longitudinal resistivity also gives the in-plane elements of the conventional resistivity tensor via a 5-point contact geometry. This is demonstrated through application to the charge-density wave compound ErTe3, and it is concluded that this method presents a significant improvement on existing techniques, particularly when measuring small anisotropies.

  View details for DOI 10.1063/1.4978908

  View details for Web of Science ID 000400392800024

  View details for PubMedID 28456271

• Magnetism and local symmetry breaking in a Mott insulator with strong spin orbit interactions NATURE COMMUNICATIONS Lu, L., Song, M., Liu, W., Reyes, A. P., Kuhns, P., Lee, H. O., Fisher, I. R., Mitrovic, V. F. 2017; 8

  Abstract

  Study of the combined effects of strong electronic correlations with spin-orbit coupling (SOC) represents a central issue in quantum materials research. Predicting emergent properties represents a huge theoretical problem since the presence of SOC implies that the spin is not a good quantum number. Existing theories propose the emergence of a multitude of exotic quantum phases, distinguishable by either local point symmetry breaking or local spin expectation values, even in materials with simple cubic crystal structure such as Ba2NaOsO6. Experimental tests of these theories by local probes are highly sought for. Our local measurements designed to concurrently probe spin and orbital/lattice degrees of freedom of Ba2NaOsO6 provide such tests. Here we show that a canted ferromagnetic phase which is preceded by local point symmetry breaking is stabilized at low temperatures, as predicted by quantum theories involving multipolar spin interactions.

  View details for DOI 10.1038/ncomms14407

  View details for PubMedID 28181502

• Superconductivity and fluctuations in Ba1-pKpFe2As2 and Ba(Fe1-nCon)(2)As-2 PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS Boehm, T., Ahangharnejhad, R. H., Jost, D., Baum, A., Muschler, B., Kretzschmar, F., Adelmann, P., Wolf, T., Wen, H., Chu, J., Fisher, I. R., Hackl, R. 2017; 254 (1)

  View details for DOI 10.1002/pssb.201600308

  View details for Web of Science ID 000393320600023

• Scaling of the Stress and Temperature Dependence of the Optical Anisotropy in Ba(Fe1-x Co (x) )(2)As-2 JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM Mirri, C., Dusza, A., Bastelberger, S., Chu, J., Kuo, H., Fisher, I. R., Degiorgi, L. 2016; 29 (12): 3053-3057

  View details for DOI 10.1007/s10948-016-3773-y

  View details for Web of Science ID 000390030600011

• Fermi surface evolution of Na-doped PbTe studied through density functional theory calculations and Shubnikov-de Haas measurements PHYSICAL REVIEW B Giraldo-Gallo, P., Sangiorgio, B., Walmsley, P., Silverstein, H. J., Fechner, M., Riggs, S. C., Geballe, T. H., Spaldin, N. A., Fisher, I. R. 2016; 94 (19)

  View details for DOI 10.1103/PhysRevB.94.195141

  View details for Web of Science ID 000388466000001

• Multiple charge density wave states at the surface of TbTe3 PHYSICAL REVIEW B Fu, L., Kraft, A. M., Sharma, B., Singh, M., Walmsley, P., Fisher, I. R., Boyer, M. C. 2016; 94 (20)

  View details for DOI 10.1103/PhysRevB.94.205101

  View details for Web of Science ID 000386618000001

• Charge density wave modulation and gap measurements in CeTe3 PHYSICAL REVIEW B Ralevic, U., LAZAREVIC, N., Baum, A., Eiter, H., Hackl, R., Giraldo-Gallo, P., Fisher, I. R., Petrovic, C., Gajic, R., Popovic, Z. V. 2016; 94 (16)

  View details for DOI 10.1103/PhysRevB.94.165132

  View details for Web of Science ID 000385628600007

• High Current Density and Low Thermal Conductivity of Atomically Thin Semimetallic WTe2. ACS nano Mleczko, M. J., Xu, R. L., Okabe, K., Kuo, H., Fisher, I. R., Wong, H. P., Nishi, Y., Pop, E. 2016; 10 (8): 7507-7514

  Abstract

  Two-dimensional (2D) semimetals beyond graphene have been relatively unexplored in the atomically thin limit. Here, we introduce a facile growth mechanism for semimetallic WTe2 crystals and then fabricate few-layer test structures while carefully avoiding degradation from exposure to air. Low-field electrical measurements of 80 nm to 2 μm long devices allow us to separate intrinsic and contact resistance, revealing metallic response in the thinnest encapsulated and stable WTe2 devices studied to date (3-20 layers thick). High-field electrical measurements and electrothermal modeling demonstrate that ultrathin WTe2 can carry remarkably high current density (approaching 50 MA/cm(2), higher than most common interconnect metals) despite a very low thermal conductivity (of the order ∼3 Wm(-1) K(-1)). These results suggest several pathways for air-stable technological viability of this layered semimetal.

  View details for DOI 10.1021/acsnano.6b02368

  View details for PubMedID 27434729

• Critical spin fluctuations and the origin of nematic order in Ba(Fe1-xCox)(2)As-2 NATURE PHYSICS Kretzschmar, F., Boehm, T., Karahasanovic, U., Muschler, B., Baum, A., Jost, D., Schmalian, J., Caprara, S., Grilli, M., Di Castro, C., Analytis, J. G., Chu, J., Fisher, I. R., Hackl, R. 2016; 12 (6): 560-?

  View details for DOI 10.1038/NPHYS3634

  View details for Web of Science ID 000377475700014

• Measurement of the B-1g and B-2g components of the elastoresistivity tensor for tetragonal materials via transverse resistivity configurations REVIEW OF SCIENTIFIC INSTRUMENTS Shapiro, M. C., Hristov, A. T., Palmstrom, J. C., Chu, J., Fisher, I. R. 2016; 87 (6)

  Abstract

  The elastoresistivity tensor mij,kl relates changes in resistivity to strains experienced by a material. As a fourth-rank tensor, it contains considerably more information about the material than the simpler (second-rank) resistivity tensor; in particular, for a tetragonal material, the B1g and B2g components of the elastoresistivity tensor (mxx,xx - mxx,yy and 2mxy,xy, respectively) can be related to its nematic susceptibility. Previous experimental probes of this quantity have focused exclusively on differential longitudinal elastoresistance measurements, which determine the induced resistivity anisotropy arising from anisotropic in-plane strain based on the difference of two longitudinal resistivity measurements. Here we describe a complementary technique based on transverse elastoresistance measurements. This new approach is advantageous because it directly determines the strain-induced resistivity anisotropy from a single transverse measurement. To demonstrate the efficacy of this new experimental protocol, we present transverse elastoresistance measurements of the 2mxy,xy elastoresistivity coefficient of BaFe2As2, a representative iron-pnictide that has previously been characterized via differential longitudinal elastoresistance measurements.

  View details for DOI 10.1063/1.4953334

  View details for Web of Science ID 000379177000049

  View details for PubMedID 27370465

• Ubiquitous signatures of nematic quantum criticality in optimally doped Fe-based superconductors SCIENCE Kuo, H., Chu, J., Palmstrom, J. C., Kivelson, S. A., Fisher, I. R. 2016; 352 (6288): 958-962

  Abstract

  A key actor in the conventional theory of superconductivity is the induced interaction between electrons mediated by the exchange of virtual collective fluctuations (phonons in the case of conventional s-wave superconductors). Other collective modes that can play the same role, especially spin fluctuations, have been widely discussed in the context of high-temperature and heavy Fermion superconductors. The strength of such collective fluctuations is measured by the associated susceptibility. Here we use differential elastoresistance measurements from five optimally doped iron-based superconductors to show that divergent nematic susceptibility appears to be a generic feature in the optimal doping regime of these materials. This observation motivates consideration of the effects of nematic fluctuations on the superconducting pairing interaction in this family of compounds and possibly beyond.

  View details for DOI 10.1126/science.aab0103

  View details for Web of Science ID 000376147800040

  View details for PubMedID 27199422

• NMR Evidence for Inhomogeneous Nematic Fluctuations in BaFe2 (As1-xPx)(2) PHYSICAL REVIEW LETTERS Dioguardi, A. P., Kissikov, T., Lin, C. H., Shirer, K. R., Lawson, M. M., Grafe, H., Chu, J., Fisher, I. R., Fernandes, R. M., Curro, N. J. 2016; 116 (10)

  Abstract

  We present evidence for nuclear spin-lattice relaxation driven by glassy nematic fluctuations in isovalent P-doped BaFe_{2}As_{2} single crystals. Both the ^{75}As and ^{31}P sites exhibit a stretched-exponential relaxation similar to the electron-doped systems. By comparing the hyperfine fields and the relaxation rates at these sites we find that the As relaxation cannot be explained solely in terms of magnetic spin fluctuations. We demonstrate that nematic fluctuations couple to the As nuclear quadrupolar moment and can explain the excess relaxation. These results suggest that glassy nematic dynamics are a common phenomenon in the iron-based superconductors.

  View details for DOI 10.1103/PhysRevLett.116.107202

  View details for Web of Science ID 000371722500009

  View details for PubMedID 27015507

• Dichroism in the Parent Ferropnictide BaFe2As2 Across the Nematic Phase Transition JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM Chinotti, M., Mirri, C., Dusza, A., Bastelberger, S., Degiorgi, L., Chu, J., Kuo, H., Fisher, I. R. 2016; 29 (3): 667-672

  View details for DOI 10.1007/s10948-015-3292-2

  View details for Web of Science ID 000371089500026

• Electrodynamic response in the electronic nematic phase of BaFe2As2 PHYSICAL REVIEW B Mirri, C., Dusza, A., Bastelberger, S., Chinotti, M., Chu, J., Kuo, H., Fisher, I. R., Degiorgi, L. 2016; 93 (8)

  View details for DOI 10.1103/PhysRevB.93.085114

  View details for Web of Science ID 000369405900008

• Ultrafast resonant soft x-ray diffraction dynamics of the charge density wave in TbTe3 PHYSICAL REVIEW B Moore, R. G., Lee, W. S., Kirchman, P. S., Chuang, Y. D., Kemper, A. F., Trigo, M., Patthey, L., Lu, D. H., Krupin, O., Yi, M., Reis, D. A., Doering, D., Denes, P., Schlotter, W. F., Turner, J. J., Hays, G., Hering, P., Benson, T., Chu, J., Devereaux, T. P., Fisher, I. R., Hussain, Z., Shen, Z. 2016; 93 (2)

  View details for DOI 10.1103/PhysRevB.93.024304

  View details for Web of Science ID 000369218500004

• Persistent order due to transiently enhanced nesting in an electronically excited charge density wave. Nature communications Rettig, L., Cortés, R., Chu, J., Fisher, I. R., Schmitt, F., Moore, R. G., Shen, Z., Kirchmann, P. S., Wolf, M., Bovensiepen, U. 2016; 7: 10459-?

  Abstract

  Non-equilibrium conditions may lead to novel properties of materials with broken symmetry ground states not accessible in equilibrium as vividly demonstrated by non-linearly driven mid-infrared active phonon excitation. Potential energy surfaces of electronically excited states also allow to direct nuclear motion, but relaxation of the excess energy typically excites fluctuations leading to a reduced or even vanishing order parameter as characterized by an electronic energy gap. Here, using femtosecond time- and angle-resolved photoemission spectroscopy, we demonstrate a tendency towards transient stabilization of a charge density wave after near-infrared excitation, counteracting the suppression of order in the non-equilibrium state. Analysis of the dynamic electronic structure reveals a remaining energy gap in a highly excited transient state. Our observation can be explained by a competition between fluctuations in the electronically excited state, which tend to reduce order, and transiently enhanced Fermi surface nesting stabilizing the order.

  View details for DOI 10.1038/ncomms10459

  View details for PubMedID 26804717

  View details for PubMedCentralID PMC4737756

• Symmetry constraints on the elastoresistivity tensor PHYSICAL REVIEW B Shapiro, M. C., Hlobil, P., Hristov, A. T., Maharaj, A. V., Fisher, I. R. 2015; 92 (23)

  View details for DOI 10.1103/PhysRevB.92.235147

  View details for Web of Science ID 000367377100003

• Origin of the Resistive Anisotropy in the Electronic Nematic Phase of BaFe(2)As(2) Revealed by Optical Spectroscopy. Physical review letters Mirri, C., Dusza, A., Bastelberger, S., Chinotti, M., Degiorgi, L., Chu, J., Kuo, H., Fisher, I. R. 2015; 115 (10): 107001-?

  Abstract

  We perform, as a function of uniaxial stress, an optical-reflectivity investigation of the representative "parent" ferropnictide BaFe_{2}As_{2} in a broad spectral range, across the tetragonal-to-orthorhombic phase transition and the onset of the long-range antiferromagnetic (AFM) order. The infrared response reveals that the dc transport anisotropy in the orthorhombic AFM state is determined by the interplay between the Drude spectral weight and the scattering rate, but that the dominant effect is clearly associated with the metallic spectral weight. In the paramagnetic tetragonal phase, though, the dc resistivity anisotropy of strained samples is almost exclusively due to stress-induced changes in the Drude weight rather than in the scattering rate, definitively establishing the anisotropy of the Fermi surface parameters as the primary effect driving the dc transport properties in the electronic nematic state.

  View details for PubMedID 26382696

• Origin of the Resistive Anisotropy in the Electronic Nematic Phase of BaFe2As2 Revealed by Optical Spectroscopy PHYSICAL REVIEW LETTERS Mirri, C., Dusza, A., Bastelberger, S., Chinotti, M., Degiorgi, L., Chu, J., Kuo, H., Fisher, I. R. 2015; 115 (10)

  View details for DOI 10.1103/PhysRevLett.115.107001

  View details for Web of Science ID 000360335900013

• Transfer of spectral weight across the gap of Sr2IrO4 induced by La doping PHYSICAL REVIEW B Brouet, V., Mansart, J., Perfetti, L., Piovera, C., Vobornik, I., Le Fevre, P., Bertran, F., Riggs, S. C., SHAPIRO, M. C., Giraldo-Gallo, P., Fisher, I. R. 2015; 92 (8)

  View details for DOI 10.1103/PhysRevB.92.081117

  View details for Web of Science ID 000360269000001

• Field-induced spin density wave and spiral phases in a layered antiferromagnet PHYSICAL REVIEW B Stone, M. B., Lumsden, M. D., Garlea, V. O., Grenier, B., Ressouche, E., Samulon, E. C., Fisher, I. R. 2015; 92 (2)

  View details for DOI 10.1103/PhysRevB.92.020415

  View details for Web of Science ID 000358600700002

• Elastoconductivity as a probe of broken mirror symmetries PHYSICAL REVIEW B Hlobil, P., Maharaj, A. V., Hosur, P., SHAPIRO, M. C., Fisher, I. R., Raghu, S. 2015; 92 (3)

  View details for DOI 10.1103/PhysRevB.92.035148

  View details for Web of Science ID 000358601000003

• Wave-vector-dependent electron-phonon coupling and the charge-density-wave transition in TbTe3 PHYSICAL REVIEW B Maschek, M., Rosenkranz, S., Heid, R., Said, A. H., Giraldo-Gallo, P., Fisher, I. R., Weber, F. 2015; 91 (23)

  View details for DOI 10.1103/PhysRevB.91.235146

  View details for Web of Science ID 000357021600001

• Bulk electronic structure of Zn-Mg-Y and Zn-Mg-Dy icosahedral quasicrystals PHYSICAL REVIEW B Nayak, J., Maniraj, M., Gloskovskii, A., Krajci, M., Sebastian, S., Fisher, I. R., Horn, K., Barman, S. R. 2015; 91 (23)

  View details for DOI 10.1103/PhysRevB.91.235116

  View details for Web of Science ID 000355968500001

• Classification of collective modes in a charge density wave by momentum-dependent modulation of the electronic band structure PHYSICAL REVIEW B Leuenberger, D., Sobota, J. A., Yang, S., Kemper, A. F., Giraldo-Gallo, P., Moore, R. G., Fisher, I. R., Kirchmann, P. S., Devereaux, T. P., Shen, Z. 2015; 91 (20)

  View details for DOI 10.1103/PhysRevB.91.201106

  View details for Web of Science ID 000354985300001

• Pressure dependence of the charge-density-wave and superconducting states in GdTe3, TbTe3, and DyTe3 PHYSICAL REVIEW B Zocco, D. A., Hamlin, J. J., Grube, K., Chu, J., Kuo, H., Fisher, I. R., Maple, M. B. 2015; 91 (20)

  View details for DOI 10.1103/PhysRevB.91.205114

  View details for Web of Science ID 000354557200003

• Monotonic Doping-Dependence in the Anisotropy of the Drude Weight and Scattering Rate of Detwinned Ba(Fe1-x Co (x) )(2)As-2 Established from the Optical Conductivity JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM Dusza, A., Lucarelli, A., Chu, J., Fisher, I. R., Degiorgi, L. 2015; 28 (4): 1261-1266

  View details for DOI 10.1007/s10948-014-2901-9

  View details for Web of Science ID 000352085700011

• Evidence for a nematic component to the hidden-order parameter in URu2Si2 from differential elastoresistance measurements NATURE COMMUNICATIONS Riggs, S. C., SHAPIRO, M. C., Maharaj, A. V., Raghu, S., Bauer, E. D., Baumbach, R. E., Giraldo-Gallo, P., Wartenbe, M., Fisher, I. R. 2015; 6

  View details for DOI 10.1038/ncomms7425

  View details for Web of Science ID 000352633900009

  View details for PubMedID 25742938

• Evidence for a nematic component to the hidden-order parameter in URu2Si2 from differential elastoresistance measurements. Nature communications Riggs, S. C., SHAPIRO, M. C., Maharaj, A. V., Raghu, S., Bauer, E. D., Baumbach, R. E., Giraldo-Gallo, P., Wartenbe, M., Fisher, I. R. 2015; 6: 6425-?

  Abstract

  For materials that harbour a continuous phase transition, the susceptibility of the material to various fields can be used to understand the nature of the fluctuating order and hence the nature of the ordered state. Here we use anisotropic biaxial strain to probe the nematic susceptibility of URu2Si2, a heavy fermion material for which the nature of the low temperature 'hidden order' state has defied comprehensive understanding for over 30 years. Our measurements reveal that the fluctuating order has a nematic component, confirming reports of twofold anisotropy in the broken symmetry state and strongly constraining theoretical models of the hidden-order phase.

  View details for DOI 10.1038/ncomms7425

  View details for PubMedID 25742938

• Stripe-like nanoscale structural phase separation in superconducting BaPb(1-x)Bi(x)O3. Nature communications Giraldo-Gallo, P., Zhang, Y., Parra, C., Manoharan, H. C., Beasley, M. R., Geballe, T. H., Kramer, M. J., Fisher, I. R. 2015; 6: 8231-?

  Abstract

  The phase diagram of BaPb1-xBixO3 exhibits a superconducting dome in the proximity of a charge density wave phase. For the superconducting compositions, the material coexists as two structural polymorphs. Here we show, via high-resolution transmission electron microscopy, that the structural dimorphism is accommodated in the form of partially disordered nanoscale stripes. Identification of the morphology of the nanoscale structural phase separation enables determination of the associated length scales, which we compare with the Ginzburg-Landau coherence length. We find that the maximum Tc occurs when the superconducting coherence length matches the width of the partially disordered stripes, implying a connection between the structural phase separation and the shape of the superconducting dome.

  View details for DOI 10.1038/ncomms9231

  View details for PubMedID 26373890

• Observation of universal strong orbital-dependent correlation effects in iron chalcogenides. Nature communications Yi, M., Liu, Z., Zhang, Y., Yu, R., Zhu, J., Lee, J. J., Moore, R. G., Schmitt, F. T., Li, W., Riggs, S. C., Chu, J., Lv, B., Hu, J., Hashimoto, M., Mo, S., Hussain, Z., Mao, Z. Q., Chu, C. W., Fisher, I. R., Si, Q., Shen, Z., Lu, D. H. 2015; 6: 7777-?

  View details for DOI 10.1038/ncomms8777

  View details for PubMedID 26204461

• Observation of universal strong orbital-dependent correlation effects in iron chalcogenides. Nature communications Yi, M., Liu, Z., Zhang, Y., Yu, R., Zhu, J., Lee, J. J., Moore, R. G., Schmitt, F. T., Li, W., Riggs, S. C., Chu, J., Lv, B., Hu, J., Hashimoto, M., Mo, S., Hussain, Z., Mao, Z. Q., Chu, C. W., Fisher, I. R., Si, Q., Shen, Z., Lu, D. H. 2015; 6: 7777-?

  Abstract

  Establishing the appropriate theoretical framework for unconventional superconductivity in the iron-based materials requires correct understanding of both the electron correlation strength and the role of Fermi surfaces. This fundamental issue becomes especially relevant with the discovery of the iron chalcogenide superconductors. Here, we use angle-resolved photoemission spectroscopy to measure three representative iron chalcogenides, FeTe0.56Se0.44, monolayer FeSe grown on SrTiO3 and K0.76Fe1.72Se2. We show that these superconductors are all strongly correlated, with an orbital-selective strong renormalization in the dxy bands despite having drastically different Fermi surface topologies. Furthermore, raising temperature brings all three compounds from a metallic state to a phase where the dxy orbital loses all spectral weight while other orbitals remain itinerant. These observations establish that iron chalcogenides display universal orbital-selective strong correlations that are insensitive to the Fermi surface topology, and are close to an orbital-selective Mott phase, hence placing strong constraints for theoretical understanding of iron-based superconductors.

  View details for DOI 10.1038/ncomms8777

  View details for PubMedID 26204461

• Disorder driven metal-insulator transition in BaPb(1-x)Bi(x)O3 and inference of disorder-free critical temperature. Physical review letters Luna, K., Giraldo-Gallo, P., Geballe, T., Fisher, I., Beasley, M. 2014; 113 (17): 177004-?

  Abstract

  We performed point-contact spectroscopy tunneling measurements on single crystal BaPb(1-x)Bi(x)O(3) for 0≤x≤0.28 at temperatures T=2-40  K and find a suppression in the density of states at low bias voltages that is characteristic of disordered metals. Both the correlation gap and the zero-temperature conductivity are zero at a critical concentration x(c)=0.30. Not only does this suggests that a disorder driven metal-insulator transition occurs before the onset of the charge disproportionated charge density wave insulator, but we also explore whether a scaling theory is applicable. In addition, we estimate the disorder-free critical temperature and compare these results to Ba(1-x)K(x)BiO(3).

  View details for PubMedID 25379933

• Disorder Driven Metal-Insulator Transition in BaPb1-xBixO3 and Inference of Disorder-Free Critical Temperature PHYSICAL REVIEW LETTERS Luna, K., Giraldo-Gallo, P., Geballe, T., Fisher, I., Beasley, M. 2014; 113 (17)

  Abstract

  We performed point-contact spectroscopy tunneling measurements on single crystal BaPb(1-x)Bi(x)O(3) for 0≤x≤0.28 at temperatures T=2-40  K and find a suppression in the density of states at low bias voltages that is characteristic of disordered metals. Both the correlation gap and the zero-temperature conductivity are zero at a critical concentration x(c)=0.30. Not only does this suggests that a disorder driven metal-insulator transition occurs before the onset of the charge disproportionated charge density wave insulator, but we also explore whether a scaling theory is applicable. In addition, we estimate the disorder-free critical temperature and compare these results to Ba(1-x)K(x)BiO(3).

  View details for DOI 10.1103/PhysRevLett.113.177004

  View details for Web of Science ID 000344052700012

• Nematic-driven anisotropic electronic properties of underdoped detwinned Ba(Fe1-xCox)(2)As-2 revealed by optical spectroscopy PHYSICAL REVIEW B Mirri, C., Dusza, A., Bastelberger, S., Chu, J., Kuo, H., Fisher, I. R., Degiorgi, L. 2014; 90 (15)

  View details for DOI 10.1103/PhysRevB.90.155125

  View details for Web of Science ID 000344022600001

• Distinguishing Bulk and Surface Electron-Phonon Coupling in the Topological Insulator Bi2Se3 Using Time-Resolved Photoemission Spectroscopy PHYSICAL REVIEW LETTERS Sobota, J. A., Yang, S., Leuenberger, D., Kemper, A. F., Analytis, J. G., Fisher, I. R., Kirchmann, P. S., Devereaux, T. P., Shen, Z. 2014; 113 (15)

  Abstract

  We report time- and angle-resolved photoemission spectroscopy measurements on the topological insulator Bi(2)Se(3). We observe oscillatory modulations of the electronic structure of both the bulk and surface states at a frequency of 2.23 THz due to coherent excitation of an A(1g) phonon mode. A distinct, additional frequency of 2.05 THz is observed in the surface state only. The lower phonon frequency at the surface is attributed to the termination of the crystal and thus reduction of interlayer van der Waals forces, which serve as restorative forces for out-of-plane lattice distortions. Density functional theory calculations quantitatively reproduce the magnitude of the surface phonon softening. These results represent the first band-resolved evidence of the A(1g) phonon mode coupling to the surface state in a topological insulator.

  View details for DOI 10.1103/PhysRevLett.113.157401

  View details for Web of Science ID 000344052200011

• Distinguishing bulk and surface electron-phonon coupling in the topological insulator Bi(2)Se(3) using time-resolved photoemission spectroscopy. Physical review letters Sobota, J. A., Yang, S., Leuenberger, D., Kemper, A. F., Analytis, J. G., Fisher, I. R., Kirchmann, P. S., Devereaux, T. P., Shen, Z. 2014; 113 (15): 157401-?

  Abstract

  We report time- and angle-resolved photoemission spectroscopy measurements on the topological insulator Bi(2)Se(3). We observe oscillatory modulations of the electronic structure of both the bulk and surface states at a frequency of 2.23 THz due to coherent excitation of an A(1g) phonon mode. A distinct, additional frequency of 2.05 THz is observed in the surface state only. The lower phonon frequency at the surface is attributed to the termination of the crystal and thus reduction of interlayer van der Waals forces, which serve as restorative forces for out-of-plane lattice distortions. Density functional theory calculations quantitatively reproduce the magnitude of the surface phonon softening. These results represent the first band-resolved evidence of the A(1g) phonon mode coupling to the surface state in a topological insulator.

  View details for PubMedID 25375740

• Ultrafast electron dynamics in the topological insulator Bi2Se3 studied by time-resolved photoemission spectroscopy JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA Sobota, J. A., Yang, S., Leuenberger, D., Kemper, A. F., Analytis, J. G., Fisher, I. R., Kirchmann, P. S., Devereaux, T. P., Shen, Z. 2014; 195: 249-257

  View details for DOI 10.1016/j.elspec.2014.01.005

  View details for Web of Science ID 000342872800036

• Bandgap closure and reopening in CsAuI3 at high pressure PHYSICAL REVIEW B Wang, S., Kemper, A. F., Baldini, M., SHAPIRO, M. C., Riggs, S. C., Zhao, Z., Liu, Z., Devereaux, T. P., Geballe, T. H., Fisher, I. R., Mao, W. L. 2014; 89 (24)

  View details for DOI 10.1103/PhysRevB.89.245109

  View details for Web of Science ID 000336976400003

• Effect of disorder on the resistivity anisotropy near the electronic nematic phase transition in pure and electron-doped BaFe(2)As(2). Physical review letters Kuo, H., Fisher, I. R. 2014; 112 (22): 227001-?

  Abstract

  We show that the strain-induced resistivity anisotropy in the tetragonal state of the representative underdoped Fe arsenides BaFe_{2}As_{2}, Ba(Fe_{1-x}Co_{x})_{2}As_{2} and Ba(Fe_{1-x}Ni_{x})_{2}As_{2} is independent of disorder over a wide range of defect and impurity concentrations. This result demonstrates that the anisotropy in the in-plane resistivity in the paramagnetic orthorhombic state of this material is not due to elastic scattering from anisotropic defects. Conversely, our result can be most easily understood if the resistivity anisotropy arises primarily from an intrinsic anisotropy in the electronic structure.

  View details for PubMedID 24949785

• Effect of Disorder on the Resistivity Anisotropy Near the Electronic Nematic Phase Transition in Pure and Electron-Doped BaFe2As2 PHYSICAL REVIEW LETTERS Kuo, H., Fisher, I. R. 2014; 112 (22)

  View details for DOI 10.1103/PhysRevLett.112.227001

  View details for Web of Science ID 000336920800015

• Spectrally resolved femtosecond reflectivity relaxation dynamics in undoped spin-density wave 122-structure iron-based pnictides PHYSICAL REVIEW B Pogrebna, A., Vujicic, N., Mertelj, T., Borzda, T., Cao, G., Xu, Z. A., Chu, J., Fisher, I. R., Mihailovic, D. 2014; 89 (16)

  View details for DOI 10.1103/PhysRevB.89.165131

  View details for Web of Science ID 000335499400003

• Dynamic competition between spin-density wave order and superconductivity in underdoped Ba1-xKxFe2As2 NATURE COMMUNICATIONS Yi, M., Zhang, Y., Liu, Z., Ding, X., Chu, J., Kemper, A. F., Plonka, N., Moritz, B., Hashimoto, M., Mo, S., Hussain, Z., Devereaux, T. P., Fisher, I. R., Wen, H. H., Shen, Z., Lu, D. H. 2014; 5

  View details for DOI 10.1038/ncomms4711

  View details for Web of Science ID 000335223100002

  View details for PubMedID 24762657

• Transport near a quantum critical point in BaFe2(As1-xPx)(2) NATURE PHYSICS Analytis, J. G., Kuo, H., McDonald, R. D., Wartenbe, M., Rourke, P. M., Hussey, N. E., Fisher, I. R. 2014; 10 (3): 194-197

  View details for DOI 10.1038/NPHYS2869

  View details for Web of Science ID 000332185900014

• Hysteretic behavior in the optical response of the underdoped Fe-arsenide Ba(Fe1-xCox)(2)As-2 in the electronic nematic phase PHYSICAL REVIEW B Mirri, C., Dusza, A., Bastelberger, S., Chu, J., Kuo, H., Fisher, I. R., Degiorgi, L. 2014; 89 (6)

  View details for DOI 10.1103/PhysRevB.89.060501

  View details for Web of Science ID 000332375400002

• Coherent dynamics of the charge density wave gap in tritellurides FARADAY DISCUSSIONS Rettig, L., Chu, J., Fisher, I. R., Bovensiepen, U., Wolf, M. 2014; 171: 299-310

  Abstract

  The dynamics of the transient electronic structure in the charge density wave (CDW) system RTe3 (R = rare-earth element) is studied using time- and angle-resolved photoemission spectroscopy (trARPES). Employing a three-pulse pump-probe scheme we investigate the effect of the amplitude mode oscillations on the electronic band structure and, in particular, on the CDW energy gap. We observe coherent oscillations in both lower and upper CDW band with opposite phases, whereby two dominating frequencies are modulating the CDW order parameter. This demonstrates the existence of more than one collective amplitude mode, in contrast to a simple Peierls model. Coherent control experiments of the two amplitude modes, which are strongly coupled in equilibrium, demonstrate independent control of the modes suggesting a decoupling of both modes in the transient photoexcited state.

  View details for DOI 10.1039/c4fd00045e

  View details for Web of Science ID 000345529900016

  View details for PubMedID 25415056

• Dynamic competition between spin-density wave order and superconductivity in underdoped Ba(1-x)K(x)Fe2As2. Nature communications Yi, M., Zhang, Y., Liu, Z., Ding, X., Chu, J., Kemper, A. F., Plonka, N., Moritz, B., Hashimoto, M., Mo, S., Hussain, Z., Devereaux, T. P., Fisher, I. R., Wen, H. H., Shen, Z., Lu, D. H. 2014; 5: 3711-?

  Abstract

  An intriguing aspect of unconventional superconductivity is that it always appears in the vicinity of other competing phases, whose suppression brings the full emergence of superconductivity. In the iron pnictides, these competing phases are marked by a tetragonal-to-orthorhombic structural transition and a collinear spin-density wave (SDW) transition. There has been macroscopic evidence for competition between these phases and superconductivity as the magnitude of both the orthorhombicity and magnetic moment are suppressed in the superconducting state. Here, using angle-resolved photoemission spectroscopy on detwinned underdoped Ba(1-x)K(x)Fe2As2, we observe a coexistence of both the SDW gap and superconducting gap in the same electronic structure. Furthermore, our data reveal that following the onset of superconductivity, the SDW gap decreases in magnitude and shifts in a direction consistent with a reduction of the orbital anisotropy. This observation provides direct spectroscopic evidence for the dynamic competition between superconductivity and both SDW and electronic nematic orders in these materials.

  View details for DOI 10.1038/ncomms4711

  View details for PubMedID 24762657

• Direct Optical Coupling to an Unoccupied Dirac Surface State in the Topological Insulator Bi2Se3 PHYSICAL REVIEW LETTERS Sobota, J. A., Yang, S., Kemper, A. F., Lee, J. J., Schmitt, F. T., Li, W., Moore, R. G., Analytis, J. G., Fisher, I. R., Kirchmann, P. S., Devereaux, T. P., Shen, Z. 2013; 111 (13)

  Abstract

  We characterize the occupied and unoccupied electronic structure of the topological insulator Bi2Se3 by one-photon and two-photon angle-resolved photoemission spectroscopy and slab band structure calculations. We reveal a second, unoccupied Dirac surface state with similar electronic structure and physical origin to the well-known topological surface state. This state is energetically located 1.5 eV above the conduction band, which permits it to be directly excited by the output of a Ti:sapphire laser. This discovery demonstrates the feasibility of direct ultrafast optical coupling to a topologically protected, spin-textured surface state.

  View details for DOI 10.1103/PhysRevLett.111.136802

  View details for PubMedID 24116801

• Measurement of the elastoresistivity coefficients of the underdoped iron arsenide Ba(Fe0.975Co0.025)(2)As-2 PHYSICAL REVIEW B Kuo, H., Shapiro, M. C., Riggs, S. C., Fisher, I. R. 2013; 88 (8)

  View details for DOI 10.1103/PhysRevB.88.085113

  View details for Web of Science ID 000323033000005

• Dynamics of Photoexcited Carriers in Ba(Fe1-xCox)(2)As-2 Single Crystals with Spin-Density-Wave Ordering JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM Stojchevska, L., Mertelj, T., Chu, J., Fisher, I. R., Mihailovic, D. 2013; 26 (8): 2593-2596

  View details for DOI 10.1007/s10948-013-2141-4

  View details for Web of Science ID 000323925500005

• Inhomogeneous Superconductivity in BaPb1-xBixO3 JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM Giraldo-Gallo, P., Lee, H., Beasley, M. R., Geballe, T. H., Fisher, I. R. 2013; 26 (8): 2675-2678

  View details for DOI 10.1007/s10948-013-2158-8

  View details for Web of Science ID 000323925500022

• Distribution of Optical Spectral Weight in Detwinned Ba(Fe1-xCox)(2)As-2 JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM Dusza, A., Lucarelli, A., Chu, J., Fisher, I. R., Degiorgi, L. 2013; 26 (8): 2603-2606

  View details for DOI 10.1007/s10948-013-2143-2

  View details for Web of Science ID 000323925500007

• Direct measurement of current-phase relations in superconductor/topological insulator/superconductor junctions. Nano letters Sochnikov, I., Bestwick, A. J., Williams, J. R., Lippman, T. M., Fisher, I. R., Goldhaber-Gordon, D., Kirtley, J. R., Moler, K. A. 2013; 13 (7): 3086-3092

  Abstract

  Proximity to a superconductor is predicted to induce exotic quantum phases in topological insulators. Here, scanning superconducting quantum interference device (SQUID) microscopy reveals that aluminum superconducting rings with topologically insulating Bi2Se3 junctions exhibit a conventional, nearly sinusoidal 2π-periodic current-phase relations. Pearl vortices occur in longer junctions, indicating suppressed superconductivity in aluminum, probably due to a proximity effect. Our observations establish scanning SQUID as a general tool for characterizing proximity effects and for measuring current-phase relations in new materials systems.

  View details for DOI 10.1021/nl400997k

  View details for PubMedID 23795666

• Infrared study of the electronic structure of the metallic pyrochlore iridate Bi2Ir2O7 PHYSICAL REVIEW B Lee, Y. S., Moon, S. J., Riggs, S. C., SHAPIRO, M. C., Fisher, I. R., Fulfer, B. W., Chan, J. Y., Kemper, A. F., Basov, D. N. 2013; 87 (19)

  View details for DOI 10.1103/PhysRevB.87.195143

  View details for Web of Science ID 000319729900003

• Charge transfer and multiple density waves in the rare earth tellurides PHYSICAL REVIEW B Banerjee, A., Feng, Y., Silevitch, D. M., Wang, J., Lang, J. C., Kuo, H., Fisher, I. R., Rosenbaum, T. F. 2013; 87 (15)

  View details for DOI 10.1103/PhysRevB.87.155131

  View details for Web of Science ID 000317822500002

• Incoherent Topological Defect Recombination Dynamics in TbTe3 PHYSICAL REVIEW LETTERS Mertelj, T., Kusar, P., Kabanov, V. V., Giraldo-Gallo, P., Fisher, I. R., Mihailovic, D. 2013; 110 (15)

  View details for DOI 10.1103/PhysRevLett.110.156401

  View details for Web of Science ID 000317458400025

• Pressure-induced symmetry breaking in tetragonal CsAuI3 PHYSICAL REVIEW B Wang, S., Hirai, S., Shapiro, M. C., Riggs, S. C., Geballe, T. H., Mao, W. L., Fisher, I. R. 2013; 87 (5)

  View details for DOI 10.1103/PhysRevB.87.054104

  View details for Web of Science ID 000314681400001

• Observation of Temperature-Induced Crossover to an Orbital-Selective Mott Phase in A(x)Fe(2-y)Se(2) (A = K, Rb) Superconductors PHYSICAL REVIEW LETTERS Yi, M., Lu, D. H., Yu, R., Riggs, S. C., Chu, J., Lv, B., Liu, Z. K., Lu, M., Cui, Y., Hashimoto, M., Mo, S., Hussain, Z., Chu, C. W., Fisher, I. R., Si, Q., Shen, Z. 2013; 110 (6)

  Abstract

  Using angle-resolved photoemission spectroscopy, we observe the low-temperature state of the A(x)Fe(2-y)Se(2) (A=K, Rb) superconductors to exhibit an orbital-dependent renormalization of the bands near the Fermi level-the d(xy) bands heavily renormalized compared to the d(xz)/d(yz) bands. Upon raising the temperature to above 150 K, the system evolves into a state in which the d(xy) bands have depleted spectral weight while the d(xz)/d(yz) bands remain metallic. Combined with theoretical calculations, our observations can be consistently understood as a temperature-induced crossover from a metallic state at low temperatures to an orbital-selective Mott phase at high temperatures. Moreover, the fact that the superconducting state of A(x)Fe(2-y)Se(2) is near the boundary of such an orbital-selective Mott phase constrains the system to have sufficiently strong on-site Coulomb interactions and Hund's coupling, highlighting the nontrivial role of electron correlation in this family of iron-based superconductors.

  View details for DOI 10.1103/PhysRevLett.110.067003

  View details for PubMedID 23432294

• Observing electronic structures on ex-situ grown topological insulator thin films PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS Yao, S. H., Zhou, B., Lu, M. H., Liu, Z. K., Chen, Y. B., Analytis, J. G., Bruene, C., Dang, W. H., Mo, S., Shen, Z., Fisher, I. R., Molenkamp, L. W., Peng, H. L., Hussain, Z., Chen, Y. L. 2013; 7 (1-2): 130-132

  View details for DOI 10.1002/pssr.201206400

  View details for Web of Science ID 000318068800013

• Giant atomic displacement at a magnetic phase transition in metastable Mn3O4 PHYSICAL REVIEW B Hirai, S., dos Santos, A. M., SHAPIRO, M. C., Molaison, J. J., Pradhan, N., Guthrie, M., Tulk, C. A., Fisher, I. R., Mao, W. L. 2013; 87 (1)

  View details for DOI 10.1103/PhysRevB.87.014417

  View details for Web of Science ID 000313423300002

• Alternative route to charge density wave formation in multiband systems PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Eiter, H., Lavagnini, M., Hackl, R., Nowadnick, E. A., Kemper, A. F., Devereaux, T. P., Chu, J., Analytis, J. G., Fisher, I. R., Degiorgi, L. 2013; 110 (1): 64-69

  Abstract

  Charge and spin density waves, periodic modulations of the electron, and magnetization densities, respectively, are among the most abundant and nontrivial low-temperature ordered phases in condensed matter. The ordering direction is widely believed to result from the Fermi surface topology. However, several recent studies indicate that this common view needs to be supplemented. Here, we show how an enhanced electron-lattice interaction can contribute to or even determine the selection of the ordering vector in the model charge density wave system ErTe(3). Our joint experimental and theoretical study allows us to establish a relation between the selection rules of the electronic light scattering spectra and the enhanced electron-phonon coupling in the vicinity of band degeneracy points. This alternative proposal for charge density wave formation may be of general relevance for driving phase transitions into other broken-symmetry ground states, particularly in multiband systems, such as the iron-based superconductors.

  View details for DOI 10.1073/pnas.1214745110

  View details for Web of Science ID 000313630300027

  View details for PubMedID 23248317

  View details for PubMedCentralID PMC3538267

• Vortex structure in BaFe2(As1-x P (x) )(2) single crystals JETP LETTERS Vinnikov, L. Y., Troshina, A. G., Veschunov, I. S., Analytis, D., Fisher, I. R., Liu, Y., Lin, C. T., Fang, L., Welp, U., Kwok, W. K. 2013; 96 (10): 655-658

  View details for DOI 10.1134/S0021364012220134

  View details for Web of Science ID 000314412900010

• Time-resolved Fermi surface mapping of the charge density wave material DyTe3 18th International Conference on Ultrafast Phenomena Rettig, L., Cortes, R., Chu, J., Fisher, I. R., Schmitt, F., Kirchmann, P. S., Moore, R. G., Shen, Z., Wolf, M., Bovensiepen, U. E D P SCIENCES. 2013

  View details for DOI 10.1051/epjconf/20134103025

  View details for Web of Science ID 000320558600082

• Controlling the carriers of topological insulators by bulk and surface doping SEMICONDUCTOR SCIENCE AND TECHNOLOGY Zhou, B., Liu, Z. K., Analytis, J. G., Igarashi, K., Mo, S. K., Lu, D. H., Moore, R. G., Fisher, I. R., Sasagawa, T., Shen, Z. X., Hussain, Z., Chen, Y. L. 2012; 27 (12)

  View details for DOI 10.1088/0268-1242/27/12/124002

  View details for Web of Science ID 000311844400004

• Magnetoelastically coupled structural, magnetic, and superconducting order parameters in BaFe2(As1-xPx)(2) PHYSICAL REVIEW B Kuo, H., Analytis, J. G., Chu, J., Fernandes, R. M., Schmalian, J., Fisher, I. R. 2012; 86 (13)

  View details for DOI 10.1103/PhysRevB.86.134507

  View details for Web of Science ID 000309456300004

• Single crystal growth by self-flux method of the mixed valence gold halides Cs-2[(AuX2)-X-I][(AuX4)-X-III] (X=Br,I) JOURNAL OF CRYSTAL GROWTH Riggs, S. C., SHAPIRO, M. C., Corredor, F., Geballe, T. H., Fisher, I. R., McCandless, G. T., Chan, J. Y. 2012; 355 (1): 13-16

  View details for DOI 10.1016/j.jcrysgro.2012.06.039

  View details for Web of Science ID 000307121900003

• Divergent Nematic Susceptibility in an Iron Arsenide Superconductor SCIENCE Chu, J., Kuo, H., Analytis, J. G., Fisher, I. R. 2012; 337 (6095): 710-712

  Abstract

  Within the Landau paradigm of continuous phase transitions, ordered states of matter are characterized by a broken symmetry. Although the broken symmetry is usually evident, determining the driving force behind the phase transition can be complicated by coupling between distinct order parameters. We show how measurement of the divergent nematic susceptibility of the iron pnictide superconductor Ba(Fe(1-x)Co(x))(2)As(2) distinguishes an electronic nematic phase transition from a simple ferroelastic distortion. These measurements also indicate an electronic nematic quantum phase transition near the composition with optimal superconducting transition temperature.

  View details for DOI 10.1126/science.1221713

  View details for Web of Science ID 000307354500048

  View details for PubMedID 22879513

• Unconventional Josephson Effect in Hybrid Superconductor-Topological Insulator Devices PHYSICAL REVIEW LETTERS Williams, J. R., Bestwick, A. J., Gallagher, P., Hong, S. S., Cui, Y., Bleich, A. S., Analytis, J. G., Fisher, I. R., Goldhaber-Gordon, D. 2012; 109 (5)

  Abstract

  We report on transport properties of Josephson junctions in hybrid superconducting-topological insulator devices, which show two striking departures from the common Josephson junction behavior: a characteristic energy that scales inversely with the width of the junction, and a low characteristic magnetic field for suppressing supercurrent. To explain these effects, we propose a phenomenological model which expands on the existing theory for topological insulator Josephson junctions.

  View details for DOI 10.1103/PhysRevLett.109.056803

  View details for Web of Science ID 000306944200002

  View details for PubMedID 23006196

• Doping dependence of femtosecond quasiparticle relaxation dynamics in Ba(Fe,Co)(2)As-2 single crystals: Evidence for normal-state nematic fluctuations PHYSICAL REVIEW B Stojchevska, L., Mertelj, T., Chu, J., Fisher, I. R., Mihailovic, D. 2012; 86 (2)

  View details for DOI 10.1103/PhysRevB.86.024519

  View details for Web of Science ID 000306543900003

• Susceptibility Anisotropy in an Iron Arsenide Superconductor Revealed by X-Ray Diffraction in Pulsed Magnetic Fields PHYSICAL REVIEW LETTERS Ruff, J. P., Chu, J., Kuo, H., Das, R. K., Nojiri, H., Fisher, I. R., Islam, Z. 2012; 109 (2)

  Abstract

  In addition to unconventional high-T(c) superconductivity, the iron arsenides exhibit strong magnetoelastic coupling and a notable electronic anisotropy within the a-b plane. We relate these properties by studying underdoped Ba(Fe(1-x)Co(x))2As2 by x-ray diffraction in pulsed magnetic fields up to 27.5 T. We exploit magnetic detwinning effects to demonstrate anisotropy in the in-plane susceptibility, which develops at the structural phase transition despite the absence of magnetic order. The degree of detwinning increases smoothly with decreasing temperature, and a single-domain condition is realized over a range of field and temperature. At low temperatures we observe an activated behavior, with a large hysteretic remnant effect. Detwinning was not observed within the superconducting phase for accessible magnetic fields.

  View details for DOI 10.1103/PhysRevLett.109.027004

  View details for Web of Science ID 000306325900016

  View details for PubMedID 23030198

• Structure and magnetic properties of the pyrochlore iridate Y2Ir2O7 PHYSICAL REVIEW B SHAPIRO, M. C., Riggs, S. C., Stone, M. B., de la Cruz, C. R., Chi, S., Podlesnyak, A. A., Fisher, I. R. 2012; 85 (21)

  View details for DOI 10.1103/PhysRevB.85.214434

  View details for Web of Science ID 000305677600004

• Infrared and Raman investigation of the charge-density-wave state in rare-earth tri-telluride compounds International Workshop on Electronic Crystals (ECRYS) Lavagnini, M., Pfuner, F., Monnier, R., Degiorgi, L., Eiter, H., Tassini, L., Muschler, B., Hackl, R., Chu, J., Ru, N., Shin, K. Y., Fisher, I. R. ELSEVIER SCIENCE BV. 2012: 1864–67

  View details for DOI 10.1016/j.physb.2012.01.050

  View details for Web of Science ID 000303415000047

• STM Imaging of Impurity Resonances on Bi2Se3 PHYSICAL REVIEW LETTERS Alpichshev, Z., Biswas, R. R., Balatsky, A. V., Analytis, J. G., Chu, J., Fisher, I. R., Kapitulnik, A. 2012; 108 (20)

  Abstract

  In this Letter we present detailed study of the density of states near defects in Bi2Se3. In particular, we present data on the commonly found triangular defects in this system. While we do not find any measurable quasiparticle scattering interference effects, we do find localized resonances, which can be well fitted by theory [R. R. Biswas and A. V. Balatsky, Phys. Rev. B 81, 233405(R) (2010)] once the potential is taken to be extended to properly account for the observed defects. The data together with the fits confirm that while the local density of states around the Dirac point of the electronic spectrum at the surface is significantly disrupted near the impurity by the creation of low-energy resonance state, the Dirac point is not locally destroyed. We discuss our results in terms of the expected protected surface state of topological insulators.

  View details for DOI 10.1103/PhysRevLett.108.206402

  View details for Web of Science ID 000304064000013

  View details for PubMedID 23003161

• Field-tuned superconductor-insulator transition in BaPb1-xBixO3 PHYSICAL REVIEW B Lee, H., Zhang, Y., Kramer, M. J., Beasley, M. R., Geballe, T. H., Fisher, I. R. 2012; 85 (17)

  View details for DOI 10.1103/PhysRevB.85.174503

  View details for Web of Science ID 000310333800002

• Resonant enhancement of charge density wave diffraction in the rare-earth tritellurides PHYSICAL REVIEW B Lee, W. S., Sorini, A. P., Yi, M., Chuang, Y. D., Moritz, B., Yang, W. L., Chu, J., Kuo, H. H., Gonzalez, A. G., Fisher, I. R., Hussain, Z., Devereaux, T. P., Shen, Z. X. 2012; 85 (15)

  View details for DOI 10.1103/PhysRevB.85.155142

  View details for Web of Science ID 000303309600003

• Pressure dependence of the BaFe2As2 Fermi surface within the spin density wave state PHYSICAL REVIEW B Graf, D., Stillwell, R., Murphy, T. P., Park, J., Palm, E. C., Schlottmann, P., McDonald, R. D., Analytis, J. G., Fisher, I. R., Tozer, S. W. 2012; 85 (13)

  View details for DOI 10.1103/PhysRevB.85.134503

  View details for Web of Science ID 000302290500004

• Ultrafast Optical Excitation of a Persistent Surface-State Population in the Topological Insulator Bi2Se3 PHYSICAL REVIEW LETTERS Sobota, J. A., Yang, S., Analytis, J. G., Chen, Y. L., Fisher, I. R., Kirchmann, P. S., Shen, Z. 2012; 108 (11)

  Abstract

  Using femtosecond time- and angle-resolved photoemission spectroscopy, we investigated the nonequilibrium dynamics of the topological insulator Bi2Se3. We studied p-type Bi2Se3, in which the metallic Dirac surface state and bulk conduction bands are unoccupied. Optical excitation leads to a metastable population at the bulk conduction band edge, which feeds a nonequilibrium population of the surface state persisting for >10 ps. This unusually long-lived population of a metallic Dirac surface state with spin texture may present a channel in which to drive transient spin-polarized currents.

  View details for DOI 10.1103/PhysRevLett.108.117403

  View details for Web of Science ID 000301478400014

  View details for PubMedID 22540508

• Anisotropic in-plane optical conductivity in detwinned Ba(Fe1-xCox)(2)As-2 NEW JOURNAL OF PHYSICS Dusza, A., Lucarelli, A., Sanna, A., Massidda, S., Chu, J., Fisher, I. R., Degiorgi, L. 2012; 14

  View details for DOI 10.1088/1367-2630/14/2/023020

  View details for Web of Science ID 000302304900005

• Ultrafast pump-probe measurements of short small-polaron lifetimes in the mixed-valence perovskite Cs2Au2I6 under high pressures PHYSICAL REVIEW B Trigo, M., Chen, J., Jiang, M. P., Mao, W. L., Riggs, S. C., SHAPIRO, M. C., Fisher, I. R., Reis, D. A. 2012; 85 (8)

  View details for DOI 10.1103/PhysRevB.85.081102

  View details for Web of Science ID 000299901600002

• Robust topological surface state against direct surface contamination PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES Liu, Z. K., Chen, Y. L., Analytis, J. G., Mo, S. K., Lu, D. H., Moore, R. G., Fisher, I. R., Hussain, Z., Shen, Z. X. 2012; 44 (5): 891-894

  View details for DOI 10.1016/j.physe.2011.10.023

  View details for Web of Science ID 000303276200005

• Incommensurate magnetic order in TbTe3 JOURNAL OF PHYSICS-CONDENSED MATTER Pfuner, F., Gvasaliya, S. N., Zaharko, O., Keller, L., Mesot, J., Pomjakushin, V., Chu, J., Fisher, I. R., Degiorgi, L. 2012; 24 (3)

  Abstract

  We report a neutron diffraction study of the magnetic phase transitions in the charge-density wave (CDW) TbTe(3) compound. We discover that in the paramagnetic phase there are strong 2D-like magnetic correlations, consistent with the pronounced anisotropy of the chemical structure. A long-range incommensurate magnetic order emerges in TbTe(3) at T(mag1) = 5.78 K as a result of continuous phase transitions. We observe that near the temperature T(mag1) the magnetic Bragg peaks appear around the position (0, 0, 0.24) (or its rational multiples), that is fairly close to the propagation vector (0,0,0.29) associated with the CDW phase transition in TbTe(3). This suggests that correlations leading to the long-range magnetic order in TbTe(3) are linked to the modulations that occur in the CDW state.

  View details for DOI 10.1088/0953-8984/24/3/036001

  View details for Web of Science ID 000298641600017

  View details for PubMedID 22156023

• Low-energy quasiparticles probed by heat transport in the iron-based superconductor LaFePO PHYSICAL REVIEW B Sutherland, M., Dunn, J., Toews, W. H., O'Farrell, E., Analytis, J., Fisher, I., Hill, R. W. 2012; 85 (1)

  View details for DOI 10.1103/PhysRevB.85.014517

  View details for Web of Science ID 000299423200008

• Principles of crystal growth of intermetallic and oxide compounds from molten solutions PHILOSOPHICAL MAGAZINE Fisher, I. R., SHAPIRO, M. C., Analytis, J. G. 2012; 92 (19-21): 2401-2435

  View details for DOI 10.1080/14786435.2012.685192

  View details for Web of Science ID 000306119500003

• Superconductivity, spin and charge order, and quantum criticality in correlated electron materials Eurasia-Pacific-Summer-School and Conference on Correlated Electrons Maple, M. B., Hamlin, J. J., Zocco, D. A., Janoschek, M., Baumbach, R. E., White, B. D., Fisher, I. R., Chu, J. E D P SCIENCES. 2012

  View details for DOI 10.1051/epjconf/20122300012

  View details for Web of Science ID 000305912900011

• In-plane electronic anisotropy of underdoped '122' Fe-arsenide superconductors revealed by measurements of detwinned single crystals REPORTS ON PROGRESS IN PHYSICS Fisher, I. R., Degiorgi, L., Shen, Z. X. 2011; 74 (12)

  View details for DOI 10.1088/0034-4885/74/12/124506

  View details for Web of Science ID 000298079500007

• Ambipolar field effect in the ternary topological insulator (BixSb1-x)(2)Te-3 by composition tuning NATURE NANOTECHNOLOGY Kong, D., Chen, Y., Cha, J. J., Zhang, Q., Analytis, J. G., Lai, K., Liu, Z., Hong, S. S., Koski, K. J., Mo, S., Hussain, Z., Fisher, I. R., Shen, Z., Cui, Y. 2011; 6 (11): 705-709

  Abstract

  Topological insulators exhibit a bulk energy gap and spin-polarized surface states that lead to unique electronic properties, with potential applications in spintronics and quantum information processing. However, transport measurements have typically been dominated by residual bulk charge carriers originating from crystal defects or environmental doping, and these mask the contribution of surface carriers to charge transport in these materials. Controlling bulk carriers in current topological insulator materials, such as the binary sesquichalcogenides Bi2Te3, Sb2Te3 and Bi2Se3, has been explored extensively by means of material doping and electrical gating, but limited progress has been made to achieve nanostructures with low bulk conductivity for electronic device applications. Here we demonstrate that the ternary sesquichalcogenide (Bi(x)Sb(1-x))2Te3 is a tunable topological insulator system. By tuning the ratio of bismuth to antimony, we are able to reduce the bulk carrier density by over two orders of magnitude, while maintaining the topological insulator properties. As a result, we observe a clear ambipolar gating effect in (Bi(x)Sb(1-x))2Te3 nanoplate field-effect transistor devices, similar to that observed in graphene field-effect transistor devices. The manipulation of carrier type and density in topological insulator nanostructures demonstrated here paves the way for the implementation of topological insulators in nanoelectronics and spintronics.

  View details for DOI 10.1038/NNANO.2011.172

  View details for Web of Science ID 000296737300007

  View details for PubMedID 21963714

• Persistence of magnons in a site-diluted dimerized frustrated antiferromagnet JOURNAL OF PHYSICS-CONDENSED MATTER Stone, M. B., Podlesnyak, A., Ehlers, G., Huq, A., Samulon, E. C., SHAPIRO, M. C., Fisher, I. R. 2011; 23 (41)

  Abstract

  We present inelastic neutron scattering and thermodynamic measurements characterizing the magnetic excitations in a disordered spin-liquid antiferromagnet with non-magnetic substitution. The parent compound Ba(3)Mn(2)O(8) is a dimerized, quasi-two-dimensional geometrically frustrated quantum disordered antiferromagnet. We substitute this compound with non-magnetic V(5+) for the S=1 Mn(5+) ions, Ba(3)(Mn(1-x)V (x))(2)O(8), and find that the singlet-triplet excitations which dominate the spectrum of the parent compound persist for the full range of substitution examined, up to x=0.3. We also observe additional low-energy magnetic fluctuations which are enhanced at the greatest substitution values.

  View details for DOI 10.1088/0953-8984/23/41/416003

  View details for Web of Science ID 000295842100016

  View details for PubMedID 21952109

• Widespread spin polarization effects in photoemission from topological insulators PHYSICAL REVIEW B Jozwiak, C., Chen, Y. L., Fedorov, A. V., Analytis, J. G., Rotundu, C. R., Schmid, A. K., Denlinger, J. D., Chuang, Y., Lee, D., Fisher, I. R., Birgeneau, R. J., Shen, Z., Hussain, Z., Lanzara, A. 2011; 84 (16)

  View details for DOI 10.1103/PhysRevB.84.165113

  View details for Web of Science ID 000299004900003

• Polarized neutron diffraction study of the field-induced magnetization in the normal and superconducting states of Ba(Fe1-xCox)(2)As-2 (x=0.65) PHYSICAL REVIEW B Lester, C., Chu, J., Analytis, J. G., Stunault, A., Fisher, I. R., Hayden, S. M. 2011; 84 (13)

  View details for DOI 10.1103/PhysRevB.84.134514

  View details for Web of Science ID 000295868900008

• Revealing the dual nature of magnetism in iron pnictides and iron chalcogenides using x-ray emission spectroscopy PHYSICAL REVIEW B Gretarsson, H., Lupascu, A., Kim, J., Casa, D., Gog, T., Wu, W., Julian, S. R., Xu, Z. J., Wen, J. S., Gu, G. D., Yuan, R. H., Chen, Z. G., Wang, N., Khim, S., Kim, K. H., Ishikado, M., Jarrige, I., Shamoto, S., Chu, J., Fisher, I. R., Kim, Y. 2011; 84 (10)

  View details for DOI 10.1103/PhysRevB.84.100509

  View details for Web of Science ID 000295138100001

• Possible origin of the nonmonotonic doping dependence of the in-plane resistivity anisotropy of Ba(Fe(1)xT(x))(2)As-2 (T = Co, Ni and Cu) PHYSICAL REVIEW B Kuo, H., Chu, J., Riggs, S. C., Yu, L., McMahon, P. L., De Greve, K., Yamamoto, Y., Analytis, J. G., Fisher, I. R. 2011; 84 (5)

  View details for DOI 10.1103/PhysRevB.84.054540

  View details for Web of Science ID 000293829800022

• Nonuniversal magnetization at the BEC critical field: Application to the spin dimer compound Ba3Mn2O8 PHYSICAL REVIEW B Suh, S., Al-Hassanieh, K. A., Samulon, E. C., Fisher, I. R., Brown, S. E., Batista, C. D. 2011; 84 (5)

  View details for DOI 10.1103/PhysRevB.84.054413

  View details for Web of Science ID 000293553100005

• Heat capacity of the site-diluted spin dimer system Ba-3(Mn1-xVx)(2)O-8 PHYSICAL REVIEW B Samulon, E. C., SHAPIRO, M. C., Fisher, I. R. 2011; 84 (5)

  View details for DOI 10.1103/PhysRevB.84.054417

  View details for Web of Science ID 000293553100009

• STM imaging of a bound state along a step on the surface of the topological insulator Bi2Te3 PHYSICAL REVIEW B Alpichshev, Z., Analytis, J. G., Chu, J., Fisher, I. R., Kapitulnik, A. 2011; 84 (4)

  View details for DOI 10.1103/PhysRevB.84.041104

  View details for Web of Science ID 000292969700001

• Ultrafast electron dynamics in the charge density wave material TbTe3 NEW JOURNAL OF PHYSICS Schmitt, F., Kirchmann, P. S., Bovensiepen, U., Moore, R. G., Chu, J., Lu, D. H., Rettig, L., Wolf, M., Fisher, I. R., Shen, Z. 2011; 13

  View details for DOI 10.1088/1367-2630/13/6/063022

  View details for Web of Science ID 000292139400004

• Rapid Surface Oxidation as a Source of Surface Degradation Factor for Bi2Se3 ACS NANO Kong, D., Cha, J. J., Lai, K., Peng, H., Analytis, J. G., Meister, S., Chen, Y., Zhang, H., Fisher, I. R., Shen, Z., Cui, Y. 2011; 5 (6): 4698-4703

  Abstract

  Bismuth selenide (Bi(2)Se(3)) is a topological insulator with metallic surface states (SS) residing in a large bulk bandgap. In experiments, synthesized Bi(2)Se(3) is often heavily n-type doped due to selenium vacancies. Furthermore, it is discovered from experiments on bulk single crystals that Bi(2)Se(3) gets additional n-type doping after exposure to the atmosphere, thereby reducing the relative contribution of SS in total conductivity. In this article, transport measurements on Bi(2)Se(3) nanoribbons provide additional evidence of such environmental doping process. Systematic surface composition analyses by X-ray photoelectron spectroscopy reveal fast formation and continuous growth of native oxide on Bi(2)Se(3) under ambient conditions. In addition to n-type doping at the surface, such surface oxidation is likely the material origin of the degradation of topological SS. Appropriate surface passivation or encapsulation may be required to probe topological SS of Bi(2)Se(3) by transport measurements.

  View details for DOI 10.1021/nn200556h

  View details for Web of Science ID 000292055200052

  View details for PubMedID 21568290

• Symmetry-breaking orbital anisotropy observed for detwinned Ba(Fe1-xCox)(2)As-2 above the spin density wave transition PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Yi, M., Lu, D., Chu, J., Analytis, J. G., Sorini, A. P., Kemper, A. F., Moritz, B., Mo, S., Moore, R. G., Hashimoto, M., Lee, W., Hussain, Z., Devereaux, T. P., Fisher, I. R., Shen, Z. 2011; 108 (17): 6878-6883

  View details for DOI 10.1073/pnas.1015572108

  View details for Web of Science ID 000289888500040

• Femtosecond Coherent Non-equilibrium Electronic Ordering and Dynamics of Topological Defect in Charge Density Waves JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM Yusupov, R., Mertelj, T., Kabanov, V. V., Kusar, P., Mihailovic, D., Chu, J., Fisher, I. R., Brazovskii, S. 2011; 24 (3): 1191-1193

  View details for DOI 10.1007/s10948-010-1107-z

  View details for Web of Science ID 000289488800016

• Behavior of vortices near twin boundaries in underdoped Ba(Fe1-xCox)(2)As-2 PHYSICAL REVIEW B Kalisky, B., Kirtley, J. R., Analytis, J. G., Chu, J., Fisher, I. R., Moler, K. A. 2011; 83 (6)

  View details for DOI 10.1103/PhysRevB.83.064511

  View details for Web of Science ID 000287483600002

• Local Measurement of the Superfluid Density in the Pnictide Superconductor Ba(Fe1-xCox)(2)As-2 across the Superconducting Dome PHYSICAL REVIEW LETTERS Luan, L., Lippman, T. M., Hicks, C. W., Bert, J. A., Auslaender, O. M., Chu, J., Analytis, J. G., Fisher, I. R., Moler, K. A. 2011; 106 (6)

  Abstract

  We measure the penetration depth λab(T) in Ba(Fe(1-x)Co(x))(2)As(2) using local techniques that do not average over the sample. The superfluid density ρs(T) ≡ 1/λab(T)2 has three main features. First, ρs (T = 0) falls sharply on the underdoped side of the dome. Second, λab(T) is flat at low T at optimal doping, indicating fully gapped superconductivity, but varies more strongly in underdoped and overdoped samples, consistent with either a power law or a small second gap. Third, ρs (T) varies steeply near Tc for optimal and underdoping. These observations are consistent with an interplay between magnetic and superconducting phases.

  View details for DOI 10.1103/PhysRevLett.106.067001

  View details for Web of Science ID 000287135400006

  View details for PubMedID 21405485

• Anisotropic charge dynamics in detwinned Ba(Fe1-xCox)(2)As-2 EPL Dusza, A., Lucarelli, A., Pfuner, F., Chu, J., Fisher, I. R., Degiorgi, L. 2011; 93 (3)

  View details for DOI 10.1209/0295-5075/93/37002

  View details for Web of Science ID 000287518600016

• Anharmonic order-parameter oscillations and lattice coupling in strongly driven 1T-TaS2 and TbTe3 charge-density-wave compounds: A multiple-pulse femtosecond laser spectroscopy study PHYSICAL REVIEW B Kusar, P., Mertelj, T., Kabanov, V. V., Chu, J., Fisher, I. R., Berger, H., Forro, L., Mihailovic, D. 2011; 83 (3)

  View details for DOI 10.1103/PhysRevB.83.035104

  View details for Web of Science ID 000286765400004

• Pressure Dependent Diffraction and Spectroscopy of a Dimerized Antiferromagnet JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN Stone, M. B., Tulk, C. A., dos Santos, A., Molaison, J. J., Chang, S., Leao, J. B., Samulon, E. C., SHAPIRO, M. C., Fisher, I. R. 2011; 80

  View details for DOI 10.1143/JPSJS.80SB.SB005

  View details for Web of Science ID 000209761800005

• Single Dirac Cone Topological Surface State and Unusual Thermoelectric Property of Compounds from a New Topological Insulator Family PHYSICAL REVIEW LETTERS Chen, Y. L., Liu, Z. K., Analytis, J. G., Chu, J., Zhang, H. J., Yan, B. H., Mo, S., Moore, R. G., Lu, D. H., Fisher, I. R., Zhang, S. C., Hussain, Z., Shen, Z. 2010; 105 (26)

  Abstract

  Angle resolved photoemission spectroscopy study on TlBiTe2 and TlBiSe2 from a thallium-based ternary chalcogenides family revealed a single surface Dirac cone at the center of the Brillouin zone for both compounds. For TlBiSe2, the large bulk gap (∼200 meV) makes it a topological insulator with better mechanical properties than the previous binary 3D topological insualtor family. For TlBiTe2, the observed negative bulk gap indicates it as a semimetal, instead of a narrow-gap semiconductor as conventionally believed; this semimetality naturally explains its mysteriously small thermoelectric figure of merit comparing to other compounds in the family. Finally, the unique band structures of TlBiTe2 also suggest it as a candidate for topological superconductors.

  View details for DOI 10.1103/PhysRevLett.105.266401

  View details for Web of Science ID 000286754700014

  View details for PubMedID 21231687

• Two-dimensional surface state in the quantum limit of a topological insulator NATURE PHYSICS Analytis, J. G., McDonald, R. D., Riggs, S. C., Chu, J., Boebinger, G. S., Fisher, I. R. 2010; 6 (12): 960-964

  View details for DOI 10.1038/NPHYS1861

  View details for Web of Science ID 000284832600015

• Enhanced Fermi-Surface Nesting in Superconducting BaFe2(As1-xPx)(2) Revealed by the de Haas-van Alphen Effect PHYSICAL REVIEW LETTERS Analytis, J. G., Chu, J., McDonald, R. D., Riggs, S. C., Fisher, I. R. 2010; 105 (20)

  Abstract

  The three-dimensional Fermi-surface morphology of superconducting BaFe2(As0.37P0.63)2 with T(c)=9  K is determined using the de Haas-van Alphen effect. The inner electron pocket has a similar area and k(z) interplane warping to the observed hole pocket, revealing that the Fermi surfaces are geometrically well nested in the (π,π) direction. These results are in stark contrast to the fermiology of the nonsuperconducting phosphides (x=1), and therefore suggest an important role for nesting in pnictide superconductivity.

  View details for DOI 10.1103/PhysRevLett.105.207004

  View details for Web of Science ID 000284147800011

  View details for PubMedID 21231258

• Pinpointing gap minima in Ba(Fe0.94Co0.06)(2)As-2 via band-structure calculations and electronic Raman scattering PHYSICAL REVIEW B Mazin, I. I., Devereaux, T. P., Analytis, J. G., Chu, J., Fisher, I. R., Muschler, B., Hackl, R. 2010; 82 (18)

  View details for DOI 10.1103/PhysRevB.82.180502

  View details for Web of Science ID 000283647300002

• Coherent dynamics of macroscopic electronic order through a symmetry breaking transition NATURE PHYSICS Yusupov, R., Mertelj, T., Kabanov, V. V., Brazovskii, S., Kusar, P., Chu, J., Fisher, I. R., Mihailovic, D. 2010; 6 (9): 681-684

  View details for DOI 10.1038/NPHYS1738

  View details for Web of Science ID 000281540200017

• In-Plane Resistivity Anisotropy in an Underdoped Iron Arsenide Superconductor SCIENCE Chu, J., Analytis, J. G., De Greve, K., McMahon, P. L., Islam, Z., Yamamoto, Y., Fisher, I. R. 2010; 329 (5993): 824-826

  Abstract

  High-temperature superconductivity often emerges in the proximity of a symmetry-breaking ground state. For superconducting iron arsenides, in addition to the antiferromagnetic ground state, a small structural distortion breaks the crystal's C(4 )rotational symmetry in the underdoped part of the phase diagram. We reveal that the representative iron arsenide Ba(Fe(1)(-x)Co(x))(2)As(2) develops a large electronic anisotropy at this transition via measurements of the in-plane resistivity of detwinned single crystals, with the resistivity along the shorter b axis rho(b) being greater than rho(a). The anisotropy reaches a maximum value of ~2 for compositions in the neighborhood of the beginning of the superconducting dome. For temperatures well above the structural transition, uniaxial stress induces a resistivity anisotropy, indicating a substantial nematic susceptibility.

  View details for DOI 10.1126/science.1190482

  View details for Web of Science ID 000280809900046

  View details for PubMedID 20705856

• Massive Dirac Fermion on the Surface of a Magnetically Doped Topological Insulator SCIENCE Chen, Y. L., Chu, J., Analytis, J. G., Liu, Z. K., Igarashi, K., Kuo, H., Qi, X. L., Mo, S. K., Moore, R. G., Lu, D. H., Hashimoto, M., Sasagawa, T., Zhang, S. C., Fisher, I. R., Hussain, Z., Shen, Z. X. 2010; 329 (5992): 659-662

  Abstract

  In addition to a bulk energy gap, topological insulators accommodate a conducting, linearly dispersed Dirac surface state. This state is predicted to become massive if time reversal symmetry is broken, and to become insulating if the Fermi energy is positioned inside both the surface and bulk gaps. We introduced magnetic dopants into the three-dimensional topological insulator dibismuth triselenide (Bi2Se3) to break the time reversal symmetry and further position the Fermi energy inside the gaps by simultaneous magnetic and charge doping. The resulting insulating massive Dirac fermion state, which we observed by angle-resolved photoemission, paves the way for studying a range of topological phenomena relevant to both condensed matter and particle physics.

  View details for DOI 10.1126/science.1189924

  View details for Web of Science ID 000280602700032

  View details for PubMedID 20689013

• Charge dynamics of Co-doped BaFe2As2 NEW JOURNAL OF PHYSICS Lucarelli, A., Dusza, A., Pfuner, F., Lerch, P., Analytis, J. G., Chu, J., Fisher, I. R., Degiorgi, L. 2010; 12

  View details for DOI 10.1088/1367-2630/12/7/073036

  View details for Web of Science ID 000281233600003

• In-plane electronic anisotropy in underdoped Ba(Fe1-xCox)(2)As-2 revealed by partial detwinning in a magnetic field PHYSICAL REVIEW B Chu, J., Analytis, J. G., Press, D., De Greve, K., Ladd, T. D., Yamamoto, Y., Fisher, I. R. 2010; 81 (21)

  View details for DOI 10.1103/PhysRevB.81.214502

  View details for Web of Science ID 000278300700004

• Bulk Fermi surface coexistence with Dirac surface state in Bi2Se3: A comparison of photoemission and Shubnikov-de Haas measurements PHYSICAL REVIEW B Analytis, J. G., Chu, J., Chen, Y., Corredor, F., McDonald, R. D., Shen, Z. X., Fisher, I. R. 2010; 81 (20)

  View details for DOI 10.1103/PhysRevB.81.205407

  View details for Web of Science ID 000278144500083

• Temperature dependence of the excitation spectrum in the charge-density-wave ErTe3 and HoTe3 systems PHYSICAL REVIEW B Pfuner, F., Lerch, P., Chu, J., Kuo, H., Fisher, I. R., Degiorgi, L. 2010; 81 (19)

  View details for DOI 10.1103/PhysRevB.81.195110

  View details for Web of Science ID 000278142000033

• Stripes of increased diamagnetic susceptibility in underdoped superconducting Ba(Fe(1-x)Cox)(2)As-2 single crystals: Evidence for an enhanced superfluid density at twin boundaries PHYSICAL REVIEW B Kalisky, B., Kirtley, J. R., Analytis, J. G., Chu, J., Vailionis, A., Fisher, I. R., Moler, K. A. 2010; 81 (18)

  View details for DOI 10.1103/PhysRevB.81.184513

  View details for Web of Science ID 000278141800092

• Correlation of anomalous normal state properties with superconductivity in Pb1-x-yTlxInyTe PHYSICAL REVIEW B Erickson, A. S., Breznay, N. P., Nowadnick, E. A., Geballe, T. H., Fisher, I. R. 2010; 81 (13)

  View details for DOI 10.1103/PhysRevB.81.134521

  View details for Web of Science ID 000277207900096

• Local measurement of the penetration depth in the pnictide superconductor Ba(Fe0.95Co0.05)(2)As-2 PHYSICAL REVIEW B Luan, L., Auslaender, O. M., Lippman, T. M., Hicks, C. W., Kalisky, B., Chu, J., Analytis, J. G., Fisher, I. R., Kirtley, J. R., Moler, K. A. 2010; 81 (10)

  View details for DOI 10.1103/PhysRevB.81.100501

  View details for Web of Science ID 000276248700020

• Anisotropic phase diagram of the frustrated spin dimer compound Ba3Mn2O8 PHYSICAL REVIEW B Samulon, E. C., Al-Hassanieh, K. A., Jo, Y., SHAPIRO, M. C., Balicas, L., Batista, C. D., Fisher, I. R. 2010; 81 (10)

  View details for DOI 10.1103/PhysRevB.81.104421

  View details for Web of Science ID 000276248700083

• Dispersive spin fluctuations in the nearly optimally doped superconductor Ba(Fe1-xCox)(2)As-2 (x=0.065) PHYSICAL REVIEW B Lester, C., Chu, J., Analytis, J. G., Perring, T. G., Fisher, I. R., Hayden, S. M. 2010; 81 (6)

  View details for DOI 10.1103/PhysRevB.81.064505

  View details for Web of Science ID 000274998100095

• Microwave surface impedance measurements of T1(x)Pb(1-x)Te: A proposed negative-U induced superconductor PHYSICAL REVIEW B BAKER, P. J., Ormeno, R. J., Gough, C. E., Matsushita, Y., Fisher, I. R. 2010; 81 (6)

  View details for DOI 10.1103/PhysRevB.81.064506

  View details for Web of Science ID 000274998100096

• Fermi surface evolution across multiple charge density wave transitions in ErTe3 PHYSICAL REVIEW B Moore, R. G., Brouet, V., He, R., Lu, D. H., Ru, N., Chu, J., Fisher, I. R., Shen, Z. 2010; 81 (7)

  View details for DOI 10.1103/PhysRevB.81.073102

  View details for Web of Science ID 000274998200002

• Raman scattering evidence for a cascade evolution of the charge-density-wave collective amplitude mode PHYSICAL REVIEW B Lavagnini, M., Eiter, H., Tassini, L., Muschler, B., Hackl, R., Monnier, R., Chu, J., Fisher, I. R., Degiorgi, L. 2010; 81 (8)

  View details for DOI 10.1103/PhysRevB.81.081101

  View details for Web of Science ID 000275053300001

• Bulk electronic structure of optimally doped Ba(Fe1-xCox)(2)As-2 PHYSICAL REVIEW B Utfeld, C., Laverock, J., Haynes, T. D., Dugdale, S. B., Duffy, J. A., Butchers, M. W., Taylor, J. W., Giblin, S. R., Analytis, J. G., Chu, J., Fisher, I. R., Itou, M., Sakurai, Y. 2010; 81 (6)

  View details for DOI 10.1103/PhysRevB.81.064509

  View details for Web of Science ID 000274998100099

• Observation of two separate charge density wave transitions in Gd2Te5 via transmission electron microscopy and high-resolution X-ray diffraction JOURNAL OF ALLOYS AND COMPOUNDS Shin, K. Y., Ru, N., Fisher, I. R., Condron, C. L., Toney, M. F., Wu, Y. Q., Kramer, M. J. 2010; 489 (2): 332-335

  View details for DOI 10.1016/j.jallcom.2009.09.154

  View details for Web of Science ID 000273251000005

• STM Imaging of Electronic Waves on the Surface of Bi2Te3: Topologically Protected Surface States and Hexagonal Warping Effects PHYSICAL REVIEW LETTERS Alpichshev, Z., Analytis, J. G., Chu, J., Fisher, I. R., Chen, Y. L., Shen, Z. X., Fang, A., Kapitulnik, A. 2010; 104 (1)

  Abstract

  Scanning tunneling spectroscopy studies on high-quality Bi2Te3 crystals exhibit perfect correspondence to angle-resolved photoemission spectroscopy data, hence enabling identification of different regimes measured in the local density of states (LDOS). Oscillations of LDOS near a step are analyzed. Within the main part of the surface band oscillations are strongly damped, supporting the hypothesis of topological protection. At higher energies, as the surface band becomes concave, oscillations appear, dispersing with a wave vector that may result from a hexagonal warping term.

  View details for DOI 10.1103/PhysRevLett.104.016401

  View details for Web of Science ID 000273881900022

  View details for PubMedID 20366373

• Evidence for a charge Kondo effect in Pb1-xTlxTe from measurements of thermoelectric power PHYSICAL REVIEW B Matusiak, M., Tunnicliffe, E. M., Cooper, J. R., Matsushita, Y., Fisher, I. R. 2009; 80 (22)

  View details for DOI 10.1103/PhysRevB.80.220403

  View details for Web of Science ID 000273228500008

• Unconventional electronic reconstruction in undoped (Ba,Sr)Fe2As2 across the spin density wave transition PHYSICAL REVIEW B Yi, M., Lu, D. H., Analytis, J. G., Chu, J., Mo, S., He, R., Hashimoto, M., Moore, R. G., Mazin, I. I., Singh, D. J., Hussain, Z., Fisher, I. R., Shen, Z. 2009; 80 (17)

  View details for DOI 10.1103/PhysRevB.80.174510

  View details for Web of Science ID 000272310400081

• Band- and momentum-dependent electron dynamics in superconducting Ba(Fe1-xCox)(2)As-2 as seen via electronic Raman scattering PHYSICAL REVIEW B Muschler, B., PRESTEL, W., Hackl, R., Devereaux, T. P., Analytis, J. G., Chu, J., Fisher, I. R. 2009; 80 (18)

  View details for DOI 10.1103/PhysRevB.80.180510

  View details for Web of Science ID 000272310900035

• New correlated electron physics from new materials PHYSICA B-CONDENSED MATTER Maple, M. B., Baumbach, R. E., Hamlin, J. J., Zocco, D. A., Taylor, B. J., Butch, N. P., Jeffries, J. R., Weir, S. T., Sales, B. C., Mandrus, D., McGuire, M. A., Sefat, A. S., Jin, R., Vohra, Y. K., Chu, J., Fisher, I. R. 2009; 404 (19): 2924-2929

  View details for DOI 10.1016/j.physb.2009.07.141

  View details for Web of Science ID 000271357300011

• Evidence for a Nodal Energy Gap in the Iron-Pnictide Superconductor LaFePO from Penetration Depth Measurements by Scanning SQUID Susceptometry PHYSICAL REVIEW LETTERS Hicks, C. W., Lippman, T. M., Huber, M. E., Analytis, J. G., Chu, J., Erickson, A. S., Fisher, I. R., Moler, K. A. 2009; 103 (12)

  Abstract

  We measure changes in the penetration depth lambda of the T_{c} approximately 6 K superconductor LaFePO. In the process, scanning SQUID susceptometry is demonstrated as a technique for accurately measuring local temperature-dependent changes in lambda, ideal for studying early or difficult-to-grow materials. lambda is found to vary linearly with temperatures from 0.36 to approximately 2 K, with a slope of 143 +/- 15 A/K, suggesting line nodes in the superconducting order parameter. The linear dependence up to approximately T_{c}/3, similar to the cuprate superconductors, indicates well-developed nodes.

  View details for DOI 10.1103/PhysRevLett.103.127003

  View details for Web of Science ID 000270139000041

  View details for PubMedID 19792454

• Fermi Surface of SrFe2P2 Determined by the de Haas-van Alphen Effect PHYSICAL REVIEW LETTERS Analytis, J. G., Andrew, C. M., Coldea, A. I., McCollam, A., Chu, J., McDonald, R. D., Fisher, I. R., Carrington, A. 2009; 103 (7)

  Abstract

  We report measurements of the Fermi surface (FS) of the ternary iron-phosphide SrFe2P2 using the de Haas-van Alphen effect. The calculated FS of this compound is very similar to SrFe2As2, the parent compound of the high temperature superconductors. Our data show that the Fermi surface is composed of two electron and two hole sheets in agreement with band-structure calculations. Several of the sheets show strong c-axis warping emphasizing the importance of three dimensionality in the nonmagnetic state of the ternary pnictides. We find that the electron and hole pockets have a different topology, implying that this material does not satisfy a (pi, pi) nesting condition.

  View details for DOI 10.1103/PhysRevLett.103.076401

  View details for Web of Science ID 000269063300047

  View details for PubMedID 19792666

• Quantum oscillations in the parent pnictide BaFe2As2: Itinerant electrons in the reconstructed state PHYSICAL REVIEW B Analytis, J. G., McDonald, R. D., Chu, J., Riggs, S. C., Bangura, A. F., Kucharczyk, C., Johannes, M., Fisher, I. R. 2009; 80 (6)

  View details for DOI 10.1103/PhysRevB.80.064507

  View details for Web of Science ID 000269638800063

• Asymmetric Quintuplet Condensation in the Frustrated S = 1 Spin Dimer Compound Ba3Mn2O8 PHYSICAL REVIEW LETTERS Samulon, E. C., Kohama, Y., McDonald, R. D., SHAPIRO, M. C., Al-Hassanieh, K. A., Batista, C. D., Jaime, M., Fisher, I. R. 2009; 103 (4)

  Abstract

  Ba_{3}Mn_{2}O_{8} is a spin-dimer compound based on pairs of S = 1, 3d;{2}, Mn;{5+} ions arranged on a triangular lattice. Antiferromagnetic intradimer exchange leads to a singlet ground state in zero field, with excited triplet and quintuplet states at higher energy. High field thermodynamic measurements are used to establish the phase diagram, revealing a substantial asymmetry of the quintuplet condensate. This striking effect, all but absent for the triplet condensate, is due to a fundamental asymmetry in quantum fluctuations of the paramagnetic phases near the various critical fields.

  View details for DOI 10.1103/PhysRevLett.103.047202

  View details for Web of Science ID 000268307400064

  View details for PubMedID 19659394

• Experimental Realization of a Three-Dimensional Topological Insulator, Bi2Te3 SCIENCE Chen, Y. L., Analytis, J. G., Chu, J., Liu, Z. K., Mo, S., Qi, X. L., Zhang, H. J., Lu, D. H., Dai, X., Fang, Z., Zhang, S. C., Fisher, I. R., Hussain, Z., Shen, Z. 2009; 325 (5937): 178-181

  Abstract

  Three-dimensional topological insulators are a new state of quantum matter with a bulk gap and odd number of relativistic Dirac fermions on the surface. By investigating the surface state of Bi2Te3 with angle-resolved photoemission spectroscopy, we demonstrate that the surface state consists of a single nondegenerate Dirac cone. Furthermore, with appropriate hole doping, the Fermi level can be tuned to intersect only the surface states, indicating a full energy gap for the bulk states. Our results establish that Bi2Te3 is a simple model system for the three-dimensional topological insulator with a single Dirac cone on the surface. The large bulk gap of Bi2Te3 also points to promising potential for high-temperature spintronics applications.

  View details for DOI 10.1126/science.1173034

  View details for Web of Science ID 000267802000040

  View details for PubMedID 19520912

• Topological Change of the Fermi Surface in Ternary Iron Pnictides with Reduced c/a Ratio: A de Haas-van Alphen Study of CaFe2P2 PHYSICAL REVIEW LETTERS Coldea, A. I., Andrew, C. M., Analytis, J. G., McDonald, R. D., Bangura, A. F., Chu, J., Fisher, I. R., Carrington, A. 2009; 103 (2)

  Abstract

  We report a de Haas-van Alphen effect study of the Fermi surface of CaFe2P2 using low-temperature torque magnetometry up to 45 T. This system is a close structural analog of the collapsed tetragonal nonmagnetic phase of CaFe2As2. We find the Fermi surface of CaFe2P2 to differ from other related ternary phosphides in that its topology is highly dispersive in the c axis, being three dimensional in character and with identical mass enhancement on both electron and hole pockets ( approximately 1.5). This suggests that when the bonding between pnictogen layers becomes important nesting conditions are not fulfilled.

  View details for DOI 10.1103/PhysRevLett.103.026404

  View details for Web of Science ID 000267887800041

  View details for PubMedID 19659226

• Evidence for weak electronic correlations in iron pnictides PHYSICAL REVIEW B Yang, W. L., Sorini, A. P., Chen, C., Moritz, B., Lee, W., Vernay, F., Olalde-Velasco, P., Denlinger, J. D., Delley, B., Chu, J., Analytis, J. G., Fisher, I. R., Ren, Z. A., Yang, J., Lu, W., Zhao, Z. X., van den Brink, J., Hussain, Z., Shen, Z., Devereaux, T. P. 2009; 80 (1)

  View details for DOI 10.1103/PhysRevB.80.014508

  View details for Web of Science ID 000268617100099

• Electronic structure of the BaFe2As2 family of iron-pnictide superconductors PHYSICAL REVIEW B Yi, M., Lu, D. H., Analytis, J. G., Chu, J., Mo, S., He, R., Moore, R. G., Zhou, X. J., Chen, G. F., Luo, J. L., Wang, N. L., Hussain, Z., Singh, D. J., Fisher, I. R., Shen, Z. 2009; 80 (2)

  View details for DOI 10.1103/PhysRevB.80.024515

  View details for Web of Science ID 000268617500094

• Pressure-induced quenching of the charge-density-wave state in rare-earth tritellurides observed by x-ray diffraction PHYSICAL REVIEW B Sacchetti, A., Condron, C. L., Gvasaliya, S. N., Pfuner, F., Lavagnini, M., Baldini, M., Toney, M. F., Merlini, M., Hanfland, M., Mesot, J., Chu, J., Fisher, I. R., Postorino, P., Degiorgi, L. 2009; 79 (20)

  View details for DOI 10.1103/PhysRevB.79.201101

  View details for Web of Science ID 000266501500001

• Quantum oscillation studies of the Fermi surface of LaFePO PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS Carrington, A., Coldea, A. I., Fletcher, J. D., Hussey, N. E., Andrew, C. M., Bangura, A. F., Analytis, J. G., Chu, J., Erickson, A. S., Fisher, I. R., McDonald, R. D. 2009; 469 (9-12): 459-468

  View details for DOI 10.1016/j.physc.2009.03.045

  View details for Web of Science ID 000267191500019

• Pressure-Induced Superconducting Phase in the Charge-Density-Wave Compound Terbium Tritelluride PHYSICAL REVIEW LETTERS Hamlin, J. J., Zocco, D. A., Sayles, T. A., Maple, M. B., Chu, J., Fisher, I. R. 2009; 102 (17)

  Abstract

  A series of high-pressure electrical resistivity measurements on single crystals of TbTe3 reveal a complex phase diagram involving the interplay of superconducting, antiferromagnetic and charge-density-wave order. The onset of superconductivity reaches a maximum of almost 4 K (onset) near approximately 12.4 GPa.

  View details for DOI 10.1103/PhysRevLett.102.177002

  View details for Web of Science ID 000265948300052

  View details for PubMedID 19518815

• ARPES studies of the electronic structure of LaOFe(P, As) PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS Lu, D. H., Yi, M., Mo, S., Analytis, J. G., Chu, J., Erickson, A. S., Singh, D. J., Hussain, Z., Geballe, T. H., Fisher, I. R., Shen, Z. 2009; 469 (9-12): 452-458

  View details for DOI 10.1016/j.physc.2009.03.044

  View details for Web of Science ID 000267191500018

• Evidence for a Nodal-Line Superconducting State in LaFePO PHYSICAL REVIEW LETTERS Fletcher, J. D., Serafin, A., Malone, L., Analytis, J. G., Chu, J., Erickson, A. S., Fisher, I. R., Carrington, A. 2009; 102 (14)

  Abstract

  In several iron-arsenide superconductors there is strong evidence for a fully gapped superconducting state consistent with either a conventional s-wave symmetry or an unusual s{+/-} state where the gap changes sign between the electron and hole Fermi-surface sheets. Here we report measurements of the penetration depth lambda(T) in very clean samples of the related iron-phosphide superconductor, LaFePO, at temperatures down to approximately 100 mK. We find that lambda(T) varies approximately linearly with T strongly suggesting the presence of gap nodes in this compound. Taken together with other data, this suggests the gap function is not universal for all pnictide superconductors.

  View details for DOI 10.1103/PhysRevLett.102.147001

  View details for Web of Science ID 000265082500058

  View details for PubMedID 19392472

• High-pressure, transport, and thermodynamic properties of CeTe3 PHYSICAL REVIEW B Zocco, D. A., Hamlin, J. J., Sayles, T. A., Maple, M. B., Chu, J., Fisher, I. R. 2009; 79 (13)

  View details for DOI 10.1103/PhysRevB.79.134428

  View details for Web of Science ID 000265942800089

• Neutron scattering study of the interplay between structure and magnetism in Ba(Fe1-xCox)(2)As-2 PHYSICAL REVIEW B Lester, C., Chu, J., Analytis, J. G., Capelli, S. C., Erickson, A. S., Condron, C. L., Toney, M. F., Fisher, I. R., Hayden, S. M. 2009; 79 (14)

  View details for DOI 10.1103/PhysRevB.79.144523

  View details for Web of Science ID 000265943200120

• Optical properties of the charge-density-wave rare-earth tri-telluride compounds: A view on PrTe3 5th International Workshop on Electronic Crystals (ECRYS-2008) Pfuner, F., Degiorgi, L., Chu, J., Ru, N., Shin, K. Y., Fisher, I. R. ELSEVIER SCIENCE BV. 2009: 533–36

  View details for DOI 10.1016/j.physb.2008.11.052

  View details for Web of Science ID 000264227400056

• Fine Structure in the Electronic Density of States near the Fermi Energy of Al-Ni-Co Decagonal Quasicrystal from Ultrafast Time-Resolved Optical Reflectivity PHYSICAL REVIEW LETTERS Mertelj, T., Oslak, A., Dolinsek, J., Fisher, I. R., Kabanov, V. V., Mihailovic, D. 2009; 102 (8)

  Abstract

  We measured the temperature and fluence dependence of the time-resolved photoinduced optical reflectivity in a decagonal Al71.9Ni11.1Co17.0 quasicrystal. We find no evidence for the relaxation of a hot thermalized electron gas as observed in metals. Instead, a quick diffusion of the hot nonthermal carriers approximately 40 nm into the bulk is detected, enhanced by the presence of a broad pseudogap. From the relaxation dynamics we find evidence for the suppression of the electronic density of states (DOS) at the Fermi energy with respect to the electronic DOS at approximately 13 meV away from the Fermi energy which is consistent with recent theoretical calculations.

  View details for DOI 10.1103/PhysRevLett.102.086405

  View details for Web of Science ID 000263816200041

  View details for PubMedID 19257762

• Pressure dependence of the single particle excitation in the charge-density-wave CeTe3 system PHYSICAL REVIEW B Lavagnini, M., Sacchetti, A., Marini, C., Valentini, M., Sopracase, R., Perucchi, A., Postorino, P., Lupi, S., Chu, J., Fisher, I. R., Degiorgi, L. 2009; 79 (7)

  View details for DOI 10.1103/PhysRevB.79.075117

  View details for Web of Science ID 000263815800039

• Charge dynamics of the spin-density-wave state in BaFe2As2 EUROPEAN PHYSICAL JOURNAL B Pfuner, F., Analytis, J. G., Chu, J., Fisher, I. R., Degiorgi, L. 2009; 67 (4): 513-517

  View details for DOI 10.1140/epjb/e2009-00062-2

  View details for Web of Science ID 000264183000005

• Enhanced superconducting pairing interaction in indium-doped tin telluride PHYSICAL REVIEW B Erickson, A. S., Chu, J., Toney, M. F., Geballe, T. H., Fisher, I. R. 2009; 79 (2)

  View details for DOI 10.1103/PhysRevB.79.024520

  View details for Web of Science ID 000262978100097

• Determination of the phase diagram of the electron-doped superconductor Ba(Fe1-xCox)(2)As-2 PHYSICAL REVIEW B Chu, J., Analytis, J. G., Kucharczyk, C., Fisher, I. R. 2009; 79 (1)

  View details for DOI 10.1103/PhysRevB.79.014506

  View details for Web of Science ID 000262977900094

• Single-Particle and Collective Mode Couplings Associated with 1-and 2-Directional Electronic Ordering in Metallic RTe3 (R=Ho,Dy,Tb) PHYSICAL REVIEW LETTERS Yusupov, R. V., Mertelj, T., Chu, J., Fisher, I. R., Mihailovic, D. 2008; 101 (24)

  Abstract

  The coupling of phonons with collective modes and single-particle gap excitations associated with one- (1d) and two-directional (2d) electronically driven charge-density wave (CDW) ordering in metallic RTe3 is investigated as a function of rare-earth ion chemical pressure (R=Tb,Dy,Ho) using femtosecond pump-probe spectroscopy. From the T dependence of the CDW gap DeltaCDW and the amplitude mode, we find that while the transition to a 1d-CDW ordered state at Tc1 initially proceeds in an exemplary mean-field-like fashion, below Tc1, DeltaCDW is depressed and departs from the mean-field behavior. The effect is apparently triggered by resonant mode mixing of the amplitude mode with a totally symmetric phonon at 1.75 THz. At low temperatures, when the state evolves into a 2d-CDW ordered state at Tc2 in the DyTe3 and HoTe3, additional much weaker mode mixing is evident but no soft mode is observed.

  View details for DOI 10.1103/PhysRevLett.101.246402

  View details for Web of Science ID 000261704100039

  View details for PubMedID 19113640

• Fermi Surface of Superconducting LaFePO Determined from Quantum Oscillations PHYSICAL REVIEW LETTERS Coldea, A. I., Fletcher, J. D., Carrington, A., Analytis, J. G., Bangura, A. F., Chu, J., Erickson, A. S., Fisher, I. R., Hussey, N. E., McDonald, R. D. 2008; 101 (21)

  Abstract

  We report extensive measurements of quantum oscillations in the normal state of the Fe-based superconductor LaFePO, (T(c) approximately 6 K) using low temperature torque magnetometry and transport in high static magnetic fields (45 T). We find that the Fermi surface is in broad agreement with the band-structure calculations with the quasiparticle mass enhanced by a factor approximately 2. The quasi-two-dimensional Fermi surface consists of nearly nested electron and hole pockets, suggesting proximity to a spin or charge density wave instability.

  View details for DOI 10.1103/PhysRevLett.101.216402

  View details for Web of Science ID 000261141500040

  View details for PubMedID 19113432

• Evidence for coupling between charge density waves and phonons in two-dimensional rare-earth tritellurides PHYSICAL REVIEW B Lavagnini, M., Baldini, M., Sacchetti, A., Di Castro, D., Delley, B., Monnier, R., Chu, J., Ru, N., Fisher, I. R., Postorino, P., Degiorgi, L. 2008; 78 (20)

  View details for DOI 10.1103/PhysRevB.78.201101

  View details for Web of Science ID 000261215400001

• Transient electronic structure and melting of a charge density wave in TbTe3 SCIENCE Schmitt, F., Kirchmann, P. S., Bovensiepen, U., Moore, R. G., Rettig, L., Krenz, M., Chu, J., Ru, N., Perfetti, L., Lu, D. H., Wolf, M., Fisher, I. R., Shen, Z. 2008; 321 (5896): 1649-1652

  Abstract

  Obtaining insight into microscopic cooperative effects is a fascinating topic in condensed matter research because, through self-coordination and collectivity, they can lead to instabilities with macroscopic impacts like phase transitions. We used femtosecond time- and angle-resolved photoelectron spectroscopy (trARPES) to optically pump and probe TbTe3, an excellent model system with which to study these effects. We drove a transient charge density wave melting, excited collective vibrations in TbTe3, and observed them through their time-, frequency-, and momentum-dependent influence on the electronic structure. We were able to identify the role of the observed collective vibration in the transition and to document the transition in real time. The information that we demonstrate as being accessible with trARPES will greatly enhance the understanding of all materials exhibiting collective phenomena.

  View details for DOI 10.1126/science.1160778

  View details for Web of Science ID 000259300400026

  View details for PubMedID 18703710

• Electronic structure of the iron-based superconductor LaOFeP NATURE Lu, D. H., Yi, M., Mo, S., Erickson, A. S., Analytis, J., Chu, J., Singh, D. J., Hussain, Z., Geballe, T. H., Fisher, I. R., Shen, Z. 2008; 455 (7209): 81-84

  Abstract

  The recent discovery of superconductivity in the iron oxypnictide family of compounds has generated intense interest. The layered crystal structure with transition-metal ions in planar square-lattice form and the discovery of spin-density-wave order near 130 K (refs 10, 11) seem to hint at a strong similarity with the copper oxide superconductors. An important current issue is the nature of the ground state of the parent compounds. Two distinct classes of theories, distinguished by the underlying band structure, have been put forward: a local-moment antiferromagnetic ground state in the strong-coupling approach, and an itinerant ground state in the weak-coupling approach. The first approach stresses on-site correlations, proximity to a Mott-insulating state and, thus, the resemblance to the high-transition-temperature copper oxides, whereas the second approach emphasizes the itinerant-electron physics and the interplay between the competing ferromagnetic and antiferromagnetic fluctuations. The debate over the two approaches is partly due to the lack of conclusive experimental information on the electronic structures. Here we report angle-resolved photoemission spectroscopy (ARPES) of LaOFeP (superconducting transition temperature, T(c) = 5.9 K), the first-reported iron-based superconductor. Our results favour the itinerant ground state, albeit with band renormalization. In addition, our data reveal important differences between these and copper-based superconductors.

  View details for DOI 10.1038/nature07263

  View details for Web of Science ID 000258890200040

  View details for PubMedID 18769435

• de Haas-van Alphen oscillations in the charge density wave compound lanthanum tritelluride LaTe3 PHYSICAL REVIEW B Ru, N., Borzi, R. A., Rost, A., Mackenzie, A. P., Laverock, J., Dugdale, S. B., Fisher, I. R. 2008; 78 (4)

  View details for DOI 10.1103/PhysRevB.78.045123

  View details for Web of Science ID 000258190400040

• Magnetic properties of the charge density wave compounds RTe3 (R = Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm) PHYSICAL REVIEW B Ru, N., Chu, J., Fisher, I. R. 2008; 78 (1)

  View details for DOI 10.1103/PhysRevB.78.012410

  View details for Web of Science ID 000258190000020

• Singlet-triplet dispersion reveals additional frustration in the triangular-lattice dimer compound Ba3Mn2O8 PHYSICAL REVIEW LETTERS Stone, M. B., Lumsden, M. D., Chang, S., Samulon, E. C., Batista, C. D., Fisher, I. R. 2008; 100 (23)

  Abstract

  We present single crystal inelastic neutron scattering measurements of the S=1 dimerized quasi-two-dimensional antiferromagnet Ba(3)Mn(2)O(8). The singlet-triplet dispersion reveals nearest-neighbor and next-nearest-neighbor ferromagnetic interactions between adjacent bilayers that compete against each other. Although the interbilayer exchange is comparable to the intrabilayer exchange, this additional frustration reduces the effective coupling along the c axis and leads to a quasi-two-dimensional behavior. In addition, the obtained exchange values are able to reproduce the four critical fields in the phase diagram.

  View details for DOI 10.1103/PhysRevLett.100.237201

  View details for Web of Science ID 000256708100066

  View details for PubMedID 18643538

• Angle-resolved photoemission study of the evolution of band structure and charge density wave properties in RTe3 (R=Y, La, Ce, Sm, Gd, Tb, and Dy) PHYSICAL REVIEW B Brouet, V., Yang, W. L., Zhou, X. J., Hussain, Z., Moore, R. G., He, R., Lu, D. H., Shen, Z. X., Laverock, J., Dugdale, S. B., Ru, N., Fisher, I. R. 2008; 77 (23)

  View details for DOI 10.1103/PhysRevB.77.235104

  View details for Web of Science ID 000257289500029

• Ordered magnetic phases of the frustrated spin-dimer compound Ba3Mn2O8 PHYSICAL REVIEW B Samulon, E. C., Jo, Y., Sengupta, P., Batista, C. D., Jaime, M., Balicas, L., Fisher, I. R. 2008; 77 (21)

  View details for DOI 10.1103/PhysRevB.77.214441

  View details for Web of Science ID 000257288900085

• Optical properties of the charge-density-wave polychalcogenide compounds R Te-2 (5) (R=Nd, Sm and Gd) EUROPEAN PHYSICAL JOURNAL B Pfuner, F., Degiorgi, L., Shin, K. Y., Fisher, I. R. 2008; 63 (1): 11-16

  View details for DOI 10.1140/epjb/e2008-00205-y

  View details for Web of Science ID 000256475300002

• Charge density wave formation in R2Te5 (R=Nd, Sm, and Gd) PHYSICAL REVIEW B Shin, K. Y., Laverock, J., Wu, Y. Q., Condron, C. L., Toney, M. F., Dugdale, S. B., Kramer, M. J., Fisher, I. R. 2008; 77 (16)

  View details for DOI 10.1103/PhysRevB.77.165101

  View details for Web of Science ID 000255457500015

• Dispersive magnetic excitations in the S=1 antiferromagnet Ba3Mn2O8 PHYSICAL REVIEW B Stone, M. B., Lumsden, M. D., Qiu, Y., Samulon, E. C., Batista, C. D., Fisher, I. R. 2008; 77 (13)

  View details for DOI 10.1103/PhysRevB.77.134406

  View details for Web of Science ID 000255457200059

• Pressure dependence of the optical properties of the charge-density-wave compound LaTe2 PHYSICAL REVIEW B Lavagnini, M., Sacchetti, A., Degiorgi, L., Arcangeletti, E., Baldassarre, L., Postorino, P., Lupi, S., Perucchi, A., Shin, K. Y., Fisher, I. R. 2008; 77 (16)

  View details for DOI 10.1103/PhysRevB.77.165132

  View details for Web of Science ID 000255457500046

• Iron deposition on the tenfold surface of the Al72Ni11Co17 decagonal quasicrystal JOURNAL OF PHYSICS-CONDENSED MATTER Wearing, L. H., Smerdon, J. A., Leung, L., Dhesi, S. S., Ledieu, J., Bencok, P., Fisher, I., Jenks, C. J., McGrath, R. 2008; 20 (1)

  View details for DOI 10.1088/0953-8984/20/01/015005

  View details for Web of Science ID 000252921800006

• Effect of chemical pressure on the charge density wave transition in rare-earth tritellurides RTe3 PHYSICAL REVIEW B Ru, N., Condron, C. L., Margulis, G. Y., Shin, K. Y., Laverock, J., Dugdale, S. B., Toney, M. F., Fisher, I. R. 2008; 77 (3)

  View details for DOI 10.1103/PhysRevB.77.035114

  View details for Web of Science ID 000252862900047

• Reply to "Comment on 'Extrinsic origin of the insulating behavior of polygrain icosahedral Al-Pd-Re quasicrystals' " PHYSICAL REVIEW B Dolinsek, J., McGuiness, P. J., Klanjsek, M., Smiljanic, I., Smontara, A., Zijlstra, E. S., Bose, S. K., Fisher, I. R., Kramer, M. J., Canfield, P. C. 2007; 76 (21)

  View details for DOI 10.1103/PhysRevB.76.216202

  View details for Web of Science ID 000251986100100

• STM studies of TbTe3: Evidence for a fully incommensurate charge density wave PHYSICAL REVIEW LETTERS Fang, A., Ru, N., Fisher, I. R., Kapitulnik, A. 2007; 99 (4)

  Abstract

  We observe unidirectional charge density wave (CDW) ordering on the quasi-2D material TbTe3 with a scanning tunneling microscope at approximately 6 K. Our analysis indicates that the CDW is fully incommensurate, with wave vector qCDW approximately 0.71x2pi/c. By imaging at various tip-sample voltages, we highlight effects of the subsurface layer and its effect on the CDW. We also observe an additional (possibly surface) dimerization and approximately 0.68x2pi/a ordering perpendicular to the CDW.

  View details for DOI 10.1103/PhysRevLett.99.046401

  View details for Web of Science ID 000248345800041

  View details for PubMedID 17678379

• Ferromagnetism in the Mott insulator Ba2NaOsO6 PHYSICAL REVIEW LETTERS Erickson, A. S., Misra, S., Miller, G. J., Gupta, R. R., Schlesinger, Z., Harrison, W. A., Kim, J. M., Fisher, I. R. 2007; 99 (1)

  Abstract

  Results are presented of single crystal structural, thermodynamic, and reflectivity measurements of the double-perovskite Ba2NaOsO6. These characterize the material as a 5d1 ferromagnetic Mott insulator with an ordered moment of approximately 0.2microB per formula unit and TC=6.8(3) K. The magnetic entropy associated with this phase transition is close to Rln2, indicating that the quartet ground state anticipated from consideration of the crystal structure is split, consistent with a scenario in which the ferromagnetism is associated with orbital ordering.

  View details for DOI 10.1103/PhysRevLett.99.016404

  View details for Web of Science ID 000247819900034

  View details for PubMedID 17678173

• Geometric frustration and dimensional reduction at a quantum critical point PHYSICAL REVIEW LETTERS Batista, C. D., Schmalian, J., Kawashima, N., Sengupta, P., Sebastian, S. E., Harrison, N., Jaime, M., Fisher, I. R. 2007; 98 (25)

  Abstract

  We show that the spatial dimensionality of the quantum critical point associated with Bose-Einstein condensation at T=0 is reduced when the underlying lattice comprises layers coupled by a frustrating interaction. Our theoretical predictions for the critical behavior correspond very well with recent measurements in BaCuSi(2)O(6) [ S. E. Sebastian et al., Nature (London) 441, 617 (2006)].

  View details for DOI 10.1103/PhysRevLett.98.257201

  View details for Web of Science ID 000247469400047

  View details for PubMedID 17678050

• Optical properties of the Ce and La ditelluride charge density wave compounds PHYSICAL REVIEW B Lavagnini, M., Sacchetti, A., Degiorgi, L., Shin, K. Y., Fisher, I. R. 2007; 75 (20)

  View details for DOI 10.1103/PhysRevB.75.205133

  View details for Web of Science ID 000246890900046

• BEC phase boundary in BaCuSi2O6 17th International Conference on Magnetism (ICM 2006) Sebastian, S. E., Harrison, N., Batista, C. D., Balicas, L., Jaime, M., Sharma, P. A., Kawashima, N., Fisher, I. R. ELSEVIER SCIENCE BV. 2007: E460–E462

  View details for DOI 10.1016/j.jmmm.2006.10.394

  View details for Web of Science ID 000247618700071

• Pressure dependence of the charge-density-wave gap in rare-earth tritellurides PHYSICAL REVIEW LETTERS Sacchetti, A., Arcangeletti, E., Perucchi, A., Baldassarre, L., Postorino, P., Lupi, S., Ru, N., Fisher, I. R., Degiorgi, L. 2007; 98 (2)

  Abstract

  We investigate the pressure dependence of the optical properties of CeTe3, which exhibits an incommensurate charge-density-wave (CDW) state already at 300 K. Our data are collected in the midinfrared spectral range at room temperature and at pressures between 0 and 9 GPa. The energy for the single particle excitation across the CDW gap decreases upon increasing the applied pressure, similarly to the chemical pressure by rare-earth substitution. The broadening of the bands upon lattice compression removes the perfect nesting condition of the Fermi surface and therefore diminishes the impact of the CDW transition on the electronic properties of RTe3.

  View details for DOI 10.1103/PhysRevLett.98.026401

  View details for Web of Science ID 000243586700041

  View details for PubMedID 17358625

• Multiple magnon modes and consequences for the Bose-Einstein condensed phase in BaCuSi2O6 PHYSICAL REVIEW LETTERS Ruegg, C., McMorrow, D. F., Normand, B., Ronnow, H. M., Sebastian, S. E., Fisher, I. R., Batista, C. D., Gvasaliya, S. N., Niedermayer, C., Stahn, J. 2007; 98 (1)

  Abstract

  The compound BaCuSi2O6 is a quantum magnet with antiferromagnetic dimers of S=1/2 moments on a quasi-2D square lattice. We have investigated its spin dynamics by inelastic neutron scattering experiments on single crystals with an energy resolution considerably higher than in an earlier study. We observe multiple magnon modes, indicating clearly the presence of magnetically inequivalent dimer sites. The more complex spin Hamiltonian revealed in our study leads to a distinct form of magnon Bose-Einstein condensate phase with a spatially modulated condensate amplitude.

  View details for DOI 10.1103/PhysRevLett.98.017202

  View details for Web of Science ID 000243379700045

  View details for PubMedID 17358501

• Role of anisotropy in the spin-dimer compound BaCuSi2O6 PHYSICAL REVIEW B Sebastian, S. E., Tanedo, P., Goddard, P. A., Lee, S., Wilson, A., Kim, S., Cox, S., McDonald, R. D., Hill, S., Harrison, N., Batista, C. D., Fisher, I. R. 2006; 74 (18)

  View details for DOI 10.1103/PhysRevB.74.180401

  View details for Web of Science ID 000242409100003

• Extrinsic origin of the insulating behavior of polygrain icosahedral Al-Pd-Re quasicrystals PHYSICAL REVIEW B Dolinsek, J., McGuiness, P. J., Klanjsek, M., Smiljanic, I., Smontara, A., Zijlstra, E. S., Bose, S. K., Fisher, I. R., Kramer, M. J., Canfield, P. C. 2006; 74 (13)

  View details for DOI 10.1103/PhysRevB.74.134201

  View details for Web of Science ID 000241723200042

• Type II superconducting parameters of Tl-doped PbTe determined from heat capacity and electronic transport measurements PHYSICAL REVIEW B Matsushita, Y., Wianecki, P. A., Sommer, A. T., Geballe, T. H., Fisher, I. R. 2006; 74 (13)

  View details for DOI 10.1103/PhysRevB.74.134512

  View details for Web of Science ID 000241723200094

• Chemical pressure and hidden one-dimensional behavior in rare-earth tri-telluride charge-density wave compounds PHYSICAL REVIEW B Sacchetti, A., Degiorgi, L., Giamarchi, T., Ru, N., Fisher, I. R. 2006; 74 (12)

  View details for DOI 10.1103/PhysRevB.74.125115

  View details for Web of Science ID 000240872500036

• Dimensional reduction at a quantum critical point NATURE Sebastian, S. E., Harrison, N., Batista, C. D., Balicas, L., Jaime, M., Sharma, P. A., Kawashima, N., Fisher, I. R. 2006; 441 (7093): 617-620

  Abstract

  Competition between electronic ground states near a quantum critical point (QCP)--the location of a zero-temperature phase transition driven solely by quantum-mechanical fluctuations--is expected to lead to unconventional behaviour in low-dimensional systems. New electronic phases of matter have been predicted to occur in the vicinity of a QCP by two-dimensional theories, and explanations based on these ideas have been proposed for significant unsolved problems in condensed-matter physics, such as non-Fermi-liquid behaviour and high-temperature superconductivity. But the real materials to which these ideas have been applied are usually rendered three-dimensional by a finite electronic coupling between their component layers; a two-dimensional QCP has not been experimentally observed in any bulk three-dimensional system, and mechanisms for dimensional reduction have remained the subject of theoretical conjecture. Here we show evidence that the Bose-Einstein condensate of spin triplets in the three-dimensional Mott insulator BaCuSi2O6 (refs 12-16) provides an experimentally verifiable example of dimensional reduction at a QCP. The interplay of correlations on a geometrically frustrated lattice causes the individual two-dimensional layers of spin-(1/2) Cu2+ pairs (spin dimers) to become decoupled at the QCP, giving rise to a two-dimensional QCP characterized by linear power law scaling distinctly different from that of its three-dimensional counterpart. Thus the very notion of dimensionality can be said to acquire an 'emergent' nature: although the individual particles move on a three-dimensional lattice, their collective behaviour occurs in lower-dimensional space.

  View details for DOI 10.1038/nature04732

  View details for Web of Science ID 000237920800043

  View details for PubMedID 16738655

• Comment on "Bose-Einstein condensation of magnons in Cs2CuCl4" PHYSICAL REVIEW LETTERS Sebastian, S. E., Zapf, V. S., Harrison, N., Batista, C. D., Sharma, P. A., Jaime, M., Fisher, I. R., Lacerda, A. 2006; 96 (18)

  View details for DOI 10.1103/PhysRevLett.96.189703

  View details for PubMedID 16712410

• Use of periodic approximants in a dynamical LEED study of the quasicrystalline tenfold surface of decagonal Al-Ni-Co PHYSICAL REVIEW B Pussi, K., Ferralis, N., Mihalkovic, M., Widom, M., Curtarolo, S., Gierer, M., Jenks, C. J., Canfield, P., Fisher, I. R., Diehl, R. D. 2006; 73 (18)

  View details for DOI 10.1103/PhysRevB.73.184203

  View details for Web of Science ID 000237950300045

• Low-temperature structural phase transition and incommensurate lattice modulation in the spin-gap compound BaCuSi2O6 PHYSICAL REVIEW B Samulon, E. C., Islam, Z., Sebastian, S. E., Brooks, P. B., McCourt, M. K., Ilavsky, J., Fisher, I. R. 2006; 73 (10)

  View details for DOI 10.1103/PhysRevB.73.100407

  View details for Web of Science ID 000236467200008

• Thermodynamic and transport properties of YTe3, LaTe3, and CeTe3 PHYSICAL REVIEW B Ru, N., Fisher, I. R. 2006; 73 (3)

  View details for DOI 10.1103/PhysRevB.73.033101

  View details for Web of Science ID 000235009500001

• Bose-einstein condensation in BaCuSi2O6 60th Yamada Conference on Research in High Magnetic Fields Harrison, N., Sebastian, S. E., Batista, C. D., Jaime, M., Balicas, L., Sharma, P. A., Kawashima, N., Fisher, I. R. IOP PUBLISHING LTD. 2006: 9–14

  View details for DOI 10.1088/1/1742-6596/51/1/002

  View details for Web of Science ID 000246201000002

• Scanning Hall probe imaging of ErNi2B2C PHYSICAL REVIEW B Bluhm, H., Sebastian, S. E., Guikema, J. W., Fisher, I. R., Moler, K. A. 2006; 73 (1)

  View details for DOI 10.1103/PhysRevB.73.014514

  View details for Web of Science ID 000235009000114

• Characteristic Bose-Einstein condensation scaling close to a quantum critical point in BaCuSi2O6 PHYSICAL REVIEW B Sebastian, S. E., Sharma, P. A., Jaime, M., Harrison, N., Correa, V., Balicas, L., Kawashima, N., Batista, C. D., Fisher, I. R. 2005; 72 (10)

  View details for DOI 10.1106/PhysRevB.72.100404

  View details for Web of Science ID 000232228800010

• Electronic structure and charge-density wave formation in LaTe1.95 and CeTe2.00 PHYSICAL REVIEW B Shin, K. Y., Brouet, V., Ru, N., Shen, Z. X., Fisher, I. R. 2005; 72 (8)

  View details for DOI 10.1103/PhysRevB.72.085132

  View details for Web of Science ID 000231564600057

• High-field behavior of the spin gap compound Sr2Cu(BO3)(2) PHYSICAL REVIEW B Sebastian, S. E., Yin, D., Tanedo, P., Jorge, G. A., Harrison, N., Jaime, M., Mozharivskyj, Y., Miller, G., Krzystek, J., Zvyagin, S. A., Fisher, I. R. 2005; 71 (21)

  View details for DOI 10.1103/PhysRevB.71.212405

  View details for Web of Science ID 000230276600009

• Magnetic structure of GdCo2Ge2 PHYSICAL REVIEW B Good, W., Kim, J., Goldman, A. I., Wermeille, D., Canfield, P. C., Cunningham, C., Islam, Z., Lang, J. C., Srajer, G., Fisher, I. R. 2005; 71 (22)

  View details for DOI 10.1103/PhysRevB.71.224427

  View details for Web of Science ID 000230276700083

• Evidence for charge Kondo effect in superconducting Tl-doped PbTe PHYSICAL REVIEW LETTERS Matsushita, Y., Bluhm, H., Geballe, T. H., Fisher, I. R. 2005; 94 (15)

  Abstract

  We report results of low-temperature thermodynamic and transport measurements of Pb1-xTlxTe single crystals for Tl concentrations up to the solubility limit of approximately x=1.5%. For all doped samples, we observe a low-temperature resistivity upturn that scales in magnitude with the Tl concentration. The temperature and field dependence of this upturn are consistent with a charge Kondo effect involving degenerate Tl valence states differing by two electrons, with a characteristic Kondo temperature T(K) approximately 6 K. The observation of such an effect supports an electronic pairing mechanism for superconductivity in this material and may account for the anomalously high T(c) values.

  View details for DOI 10.1103/PhysRevLett.94.157002

  View details for Web of Science ID 000228632500053

  View details for PubMedID 15904175

• Fermi surface nesting and charge-density wave formation in rare-earth tritellurides PHYSICAL REVIEW B Laverock, J., Dugdale, S. B., Major, Z., Alam, M. A., Ru, N., Fisher, I. R., Santi, G., Bruno, E. 2005; 71 (8)

  View details for DOI 10.1103/PhysRevB.71.085114

  View details for Web of Science ID 000228065300030

• Magneto-optic spectrum and electronic structure of single-crystal MnBi JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS Brammeier, D. P., Park, J. M., Olson, C. G., Fisher, I. R., Lynch, D. W. 2004; 283 (1): 95-102

  View details for DOI 10.1016/j.jmmm.2004.04.130

  View details for Web of Science ID 000225157600013

• An STM and SXPS study of the interaction of C-60 with the ten-fold surface of the Al72Ni11Co17 quasicrystal 22nd European Conference on Surface Science (ECOSS 22) Cox, E. J., Ledieu, J., Dhanak, V. R., Barrett, S. D., Jenks, C. J., Fisher, I., McGrath, R. ELSEVIER SCIENCE BV. 2004: 1200–1205

  View details for DOI 10.1016/j.susc.2004.06.089

  View details for Web of Science ID 000224238300098

• Fermi surface reconstruction in the CDW state of CeTe3 observed by photoemission PHYSICAL REVIEW LETTERS Brouet, V., Yang, W. L., Zhou, X. J., Hussain, Z., Ru, N., Shin, K. Y., Fisher, I. R., Shen, Z. X. 2004; 93 (12)

  Abstract

  CeTe3 is a layered compound where an incommensurate charge density wave (CDW) opens a large gap ( approximately 400 meV) in optimally nested regions of the Fermi surface (FS), whereas other sections with poorer nesting remain ungapped. Through angle-resolved photoemission, we identify bands backfolded according to the CDW periodicity. They define FS pockets formed by the intersection of the original FS and its CDW replica. Such pockets illustrate very directly the role of nesting in the CDW formation but they could not be detected so far in a CDW system. We address the reasons for the weak intensity of the folded bands, by comparing different foldings coexisting in CeTe3.

  View details for DOI 10.1103/PhysRevLett.93.126405

  View details for Web of Science ID 000223923800059

  View details for PubMedID 15447291

• Magnetic properties of single grain r-mg-cd primitive icosahedral quasicrystals (R = Y, Gd, Tb or Dy) PHILOSOPHICAL MAGAZINE Sebastian, S. E., Huie, T., Fisher, I. R., Dennis, K. W., Kramer, M. J. 2004; 84 (10): 1029-1037

  View details for DOI 10.1080/14786430310001641939

  View details for Web of Science ID 000220147600007

• Structure of the tenfold d-Al-Ni-Co quasicrystal surface PHYSICAL REVIEW B Ferralis, N., Pussi, K., Cox, E. J., Gierer, M., Ledieu, J., Fisher, I. R., Jenks, C. J., Lindroos, M., McGrath, R., Diehl, R. D. 2004; 69 (15)

  View details for DOI 10.1103/PhysRevB.69.153404

  View details for Web of Science ID 000221426800025

• Phonon dispersion curve of icosahedral Mg-Zn-Y quasicrystals 8th International Conference on Quasicrystals Brand, R. A., Voss, J., Hippert, F., Krisch, M., Sterzel, R., Assmus, W., Fisher, I. R. ELSEVIER SCIENCE BV. 2004: 207–209

  View details for DOI 10.1016/j.jnoncrysol.2003.11.040

  View details for Web of Science ID 000189274200043

• Low-energy electron diffraction study of Xe adsorption on the ten-fold decagonal Al-Ni-Co quasicrystal surface PHYSICAL REVIEW B Ferralis, N., Diehl, R. D., Pussi, K., Lindroos, M., Fisher, I., Jenks, C. J. 2004; 69 (7)

  View details for DOI 10.1103/PhysRevB.69.075410

  View details for Web of Science ID 000220055300090

• Degree of structural perfection of icosahedral quasicrystalline grains investigated by synchrotron X-ray diffractometry and imaging techniques PHILOSOPHICAL MAGAZINE Gastaldi, J., Agliozzo, S., Letoublon, A., Wang, J., Mancini, L., Klein, H., Hartwig, J., Baruchel, J., Fisher, I. R., Sato, T., Tsai, A. P., de Boissieu, A. M. 2003; 83 (1): 1-29

  View details for DOI 10.1080/0141861021000019970

  View details for Web of Science ID 000181811600002

• Surface structures of approximant phases in the Al-Pd-Mn system PHYSICAL REVIEW B Fournee, V., Ross, A. R., Lograsso, T. A., Anderegg, J. W., Dong, C., Kramer, M., Fisher, I. R., Canfield, P. C., Thiel, P. A. 2002; 66 (16)

  View details for DOI 10.1103/PhysRevB.66.165423

  View details for Web of Science ID 000179286400133

• Transport properties of icosahedral quasicrystal Al72Pd19.5Mn8.5 Quasicrystals 2001 Conference Bilusic, A., Budrovic, Z., Smontara, A., Dolinsek, J., Canfield, P. C., Fisher, I. R. ELSEVIER SCIENCE SA. 2002: 413–15

  View details for Web of Science ID 000177932400091

• Quasicrystal surfaces: potential as templates for molecular adsorption Quasicrystals 2001 Conference McGrath, R., Ledieu, J., Cox, E. J., Haq, S., Diehl, R. D., Jenks, C. J., Fisher, I., Ross, A. R., Lograsso, T. A. ELSEVIER SCIENCE SA. 2002: 432–36

  View details for Web of Science ID 000177932400095

• The local atomic structure of R-Mg-Zn (R=Y, Gd, Dy and Tb) Quasicrystals 2001 Conference Kramer, M. J., Hong, S. T., Canfield, P. C., Fisher, I. R., Corbett, J. D., Zhu, Y., Goldman, A. I. ELSEVIER SCIENCE SA. 2002: 82–86

  View details for Web of Science ID 000177932400018

• The electrical conductivity of single-grain Al-Pd-Re quasicrystals PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES Fisher, I. R., Xie, X. P., Tudosa, I., Gao, C. W., Song, C., Canfield, P. C., Kracher, A., Dennis, K., Abanoz, D., Kramer, M. J. 2002; 82 (9): 1089-1098

  View details for DOI 10.1080/13642810210122179

  View details for Web of Science ID 000175789300007

• Surface preparation and characterization of the icosahedral Al-Ga-Pd-Mn quasicrystal JOURNAL OF ALLOYS AND COMPOUNDS Heinzig, M., Jenks, C. J., Van Hove, M., Fisher, I., Canfield, P. C., Thiel, P. A. 2002; 338 (1-2): 248-252

  View details for Web of Science ID 000175886300036

• Icosahedral quasicrystal Al71Pd21Mn08 and its xi ' approximant: Linear expansivity, specific heat, magnetic susceptibility, electrical resistivity, and elastic constants PHYSICAL REVIEW B Swenson, C. A., Fisher, I. R., Anderson, N. E., Canfield, P. C., Migliori, A. 2002; 65 (18)

  View details for DOI 10.1103/PhysRevB.65.184206

  View details for Web of Science ID 000175758700048

• Infrared and optical properties of pure and cobalt-doped LuNi2B2C PHYSICAL REVIEW B Windt, M., McGuire, J. J., Room, T., Pronin, A., Timusk, T., Fisher, I. R., Canfield, P. C. 2002; 65 (6)

  View details for DOI 10.1103/PhysRevB.65.064506

  View details for Web of Science ID 000173879700093

• Microwave conductivity and penetration depth in the heavy fermion superconductor CeCoIn5 PHYSICAL REVIEW LETTERS Ormeno, R. J., Sibley, A., Gough, C. E., Sebastian, S., Fisher, I. R. 2002; 88 (4)

  Abstract

  The electrodynamic properties of the quasi-two-dimensional heavy fermion superconductor CeCoIn5 have been investigated by microwave surface impedance measurements over a wide range of microwave frequencies and temperatures. We derive a value penetration depth lambda(0) approximately 190 nm, with a strong linear term in the temperature dependence of lambda(T) below T(c)/3, consistent with a superconducting gap with line nodes. The real part of the conductivity displays a broad peak at low temperatures consistent with a decreased scattering rate of almost 2 orders of magnitude below T(c). CeCoIn5 has remarkably similar properties to those of the high-T(c) cuprates.

  View details for DOI 10.1103/PhysRevLett.88.047005

  View details for Web of Science ID 000173907500066

  View details for PubMedID 11801159

• Unusual spin-glass phase in icosahedral Tb-Mg-Zn quasicrystals PHYSICAL REVIEW B Dolinsek, J., Jaglicic, Z., Chernikov, M. A., Fisher, I. R., Canfield, P. C. 2001; 64 (22)

  View details for DOI 10.1103/PhysRevB.64.224209

  View details for Web of Science ID 000172733300038

• Observation of a spin reorientation in TbCu2Ge2 from resonant and nonresonant x-ray scattering PHYSICAL REVIEW B Song, C., Johnson, D., Wermeille, D., Goldman, A. I., Bud'ko, S. L., Fisher, I. R., Canfield, P. C. 2001; 64 (22)

  View details for DOI 10.1103/PhysRevB.64.224414

  View details for Web of Science ID 000172733300057

• Reentrant behavior in the temperature dependence of metamagnetic transitions in single crystal Nd6Fe13-xAl1+x 8th Joint Magnetism and Magnetic Materials International Magnetics Conference (MMM-INTERMAG) McCallum, R. W., Fisher, I. R., Anderson, N. E., Canfield, P. C., Kramer, M. J., Dennis, K. W. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. 2001: 2147–49

  View details for Web of Science ID 000170910900281

• High-temperature solution growth of intermetallic single crystals and quasicrystals 12th American Conference on Crystal Growth and Epitaxy Canfield, P. C., Fisher, I. R. ELSEVIER SCIENCE BV. 2001: 155–61

  View details for Web of Science ID 000169394300012

• R9Mg34Zn57 icosahedral quasicrystals: The tuning of a model spin glass 13th InTernational Conference on Solid Compounds of Transition Elements Canfield, P. C., Fisher, I. R. ELSEVIER SCIENCE SA. 2001: 443–447

  View details for Web of Science ID 000168157200085

• Structure and physical properties of the new pseudo-binary intermetallic compound Ti-11(Sb, Sn)(8) JOURNAL OF SOLID STATE CHEMISTRY Kim, H., Olmstead, M. M., Chan, J. Y., Canfield, P. C., Fisher, I. R., Henning, R. W., Schultz, A. J., Kauzlarich, S. M. 2001; 157 (1): 225-232

  View details for DOI 10.1006/jssc.2000.9080

  View details for Web of Science ID 000167634500030

• Growth of large single-grain quasicrystals from high-temperature metallic solutions 7th International Conference on Quasicrystals (ICQ7) Fisher, I. R., Kramer, M. J., Islam, Z., Wiener, T. A., Kracher, A., Ross, A. R., Lograsso, T. A., Goldman, A. I., Canfield, P. C. ELSEVIER SCIENCE SA. 2000: 10–16

  View details for Web of Science ID 000166175900003

• Plasticity of icosahedral Zn-Mg-Dy single quasicrystals 7th International Conference on Quasicrystals (ICQ7) Heggen, M., Feuerbacher, M., Schall, P., Klein, H., Fisher, I. R., Canfield, P. C., Urban, K. ELSEVIER SCIENCE SA. 2000: 781–785

  View details for Web of Science ID 000166175900180

• Heat capacities of icosahedral and hexagonal phases of Zn-Mg-Y system 7th International Conference on Quasicrystals (ICQ7) Inaba, A., Takakura, H., Tsai, A. P., Fisher, I. R., Canfield, P. C. ELSEVIER SCIENCE SA. 2000: 723–726

  View details for Web of Science ID 000166175900168

• Formation and morphological development of porosity in icosahedral Al-Pd-Mn alloys 7th International Conference on Quasicrystals (ICQ7) Ross, A. R., Wiener, T. A., Fisher, I. R., Canfield, P. C., Lograsso, T. A. ELSEVIER SCIENCE SA. 2000: 53–56

  View details for Web of Science ID 000166175900012

• Electrical resistivity, thermopower, and thermal conductivity of single grained (Y, Tb, Ho, Er)-Mg-Zn icosahedral quasicrystals 7th International Conference on Quasicrystals (ICQ7) Gianno, K., Sologubenko, A. V., Chernikov, M. A., Ott, H. R., Fisher, I. R., Canfield, P. C. ELSEVIER SCIENCE SA. 2000: 715–718

  View details for Web of Science ID 000166175900166

• Phason strain and structural perfection in the Zn-Mg-rare-earth icosahedral phases 7th International Conference on Quasicrystals (ICQ7) Letoublon, A., Fisher, I. R., Sato, T. J., de Boissieu, M., Boudard, M., Agliozzo, S., Mancini, L., Gastaldi, J., Canfield, P. C., Goldman, A. I., Tsai, A. P. ELSEVIER SCIENCE SA. 2000: 127–130

  View details for Web of Science ID 000166175900030

• Diffusion of Co-57 in decagonal Al-Ni-Co-quasicrystals 7th International Conference on Quasicrystals (ICQ7) Khoukaz, C., Galler, R., Mehrer, H., Canfield, P. C., Fisher, I. R., Feuerbacher, M. ELSEVIER SCIENCE SA. 2000: 697–701

  View details for Web of Science ID 000166175900162

• Design of a metallic Ising spin glass in the Y1-xTbxNi2Ge2 system PHYSICAL REVIEW B Wiener, T. A., Fisher, I. R., Bud'ko, S. L., Kracher, A., Canfield, P. C. 2000; 62 (22): 15056-15066

  View details for Web of Science ID 000165883800061

• Electronic structure of quasicrystalline surfaces: Effects of surface preparation and bulk structure PHYSICAL REVIEW B Fournee, V., Pinhero, P. J., Anderegg, J. W., Lograsso, T. A., Ross, A. R., Canfield, P. C., Fisher, I. R., Thiel, P. A. 2000; 62 (21): 14049-14060

  View details for Web of Science ID 000165717200050

• Unconventional electronic Raman spectra of borocarbide superconductors International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI Yang, I. S., Klein, M. V., Devereaux, T. P., Fisher, I. R., Canfield, P. C. ELSEVIER SCIENCE BV. 2000: 2259–2260

  View details for Web of Science ID 000165856000075

• Recent advances in the study of quasicrystals 14th International Congress on Electron Microscopy Fisher, I. R., Kramer, M. J., Goldman, A. I. PERGAMON-ELSEVIER SCIENCE LTD. 2000: 469–73

  View details for Web of Science ID 000087050100003

• Nonlocal effects in magnetization of high-kappa superconductors PHYSICAL REVIEW B Kogan, V. G., Bud'ko, S. L., Fisher, I. R., Canfield, P. C. 2000; 62 (13): 9077-9082

  View details for Web of Science ID 000089733800090

• Observation of a metamagnetic phase transition in an itinerant 4f system via the magneto-optic Kerr effect: Ce(Fe1-xCox)(2) PHYSICAL REVIEW B Lange, R. J., Fisher, I. R., Canfield, P. C., Antropov, V. P., Lee, S. J., Harmon, B. N., Lynch, D. W. 2000; 62 (11): 7084-7092

  View details for Web of Science ID 000089413500050

• Yb14ZnSb11: Charge balance in Zintl compounds as a route to intermediate Yb valence PHYSICAL REVIEW LETTERS Fisher, I. R., Bud'ko, S. L., Song, C., Canfield, P. C., Ozawa, T. C., Kauzlarich, S. M. 2000; 85 (5): 1120-1123

  View details for Web of Science ID 000088457000055

• Low-temperature thermal conductivity of a single-grain Y-Mg-Zn icosahedral quasicrystal PHYSICAL REVIEW B Gianno, K., Sologubenko, A. V., Chernikov, M. A., Ott, H. R., Fisher, I. R., Canfield, P. C. 2000; 62 (1): 292-300

  View details for Web of Science ID 000088037000056

• Low-temperature transport, thermal, and optical properties of single-grain quasicrystals of icosahedral phases in the Y-Mg-Zn and Tb-Mg-Zn alloy systems PHYSICAL REVIEW B Chernikov, M. A., Paschen, S., Felder, E., Vorburger, P., Ruzicka, B., Degiorgi, L., Ott, H. R., Fisher, I. R., Canfield, P. C. 2000; 62 (1): 262-272

  View details for Web of Science ID 000088037000053

• The magnetic characteristics of the Tb(Ni1-xCox)(2)Ge-2 system 22nd Rare Earth Research Conference Wiener, T. A., Fisher, I. R., Canfield, P. C. ELSEVIER SCIENCE SA. 2000: 289–292

  View details for Web of Science ID 000087312600048

• Magnetic properties of icosahedral R-Mg-Zn quasicrystals (R=Y, Tb, Dy, Ho and Er) 22nd Rare Earth Research Conference Fisher, I. R., Islam, Z., Zarestky, J., Stassis, C., Kramer, M. J., Goldman, A. I., Canfield, P. C. ELSEVIER SCIENCE SA. 2000: 223–227

  View details for Web of Science ID 000087312600035

• Non-locality and the flux line lattice square to hexagonal symmetry transition in the borocarbide superconductors 1st Euroconference on Vortex Matter in Superconductors at Extreme Scales and Conditions Eskildsen, M. R., Fisher, I. R., Gammel, P. L., Bishop, D. J., Andersen, N. H., Mortensen, K., Canfield, P. C. ELSEVIER SCIENCE BV. 2000: 320–26

  View details for Web of Science ID 000087245200058

• Interwoven magnetic and flux line structures in single crystal (Tm,Er)Ni2B2C (invited) 44th Annual Conference on Magnetism and Magnetic Materials Gammel, P. L., Lopez, D., Bishop, D. J., Eskildsen, M. R., Andersen, N. H., Mortensen, K., Fisher, I. R., Cheon, K. O., Canfield, P. C. AMER INST PHYSICS. 2000: 5544–48

  View details for Web of Science ID 000086727200282

• Optical properties and electronic structure of single crystals of EuAl2 and YbAl2 PHYSICAL REVIEW B Lee, S. J., Hong, S. Y., Fisher, I. R., Canfield, P. C., Harmon, B. N., Lynch, D. W. 2000; 61 (15): 10076-10083

  View details for Web of Science ID 000086606200051

• A LEED comparison of structural stabilities of the three high-symmetry surfaces of Al-Pd-Mn bulk quasicrystals SURFACE SCIENCE Shen, Z., Raberg, W., Heinzig, M., Jenks, C. J., Fournee, V., Van Hove, M. A., Lograsso, T. A., Delaney, D., Cai, T., Canfield, P. C., Fisher, I. R., Goldman, A. I., Kramer, M. J., Thiel, P. A. 2000; 450 (1-2): 1-11

  View details for Web of Science ID 000086200200003

• Plastic deformation of icosahedral Zn-Mg-Dy single quasicrystals PHILOSOPHICAL MAGAZINE LETTERS Heggen, M., Feuerbacher, M., Schall, P., Klein, H., Fisher, I. R., Canfield, P. C., Urban, K. 2000; 80 (3): 129-136

  View details for Web of Science ID 000086139000001

• Flux line lattice symmetries in the borocarbide superconductors 1st Regional Conference on Magnetic and Superconducting Materials (MSM-99) Eskildsen, M. R., Gammel, P. L., Bishop, D. J., Andersen, N. H., Mortensen, K., Fisher, I. R., Canfield, P. C. WORLD SCIENTIFIC PUBL CO PTE LTD. 2000: 433–446

  View details for Web of Science ID 000169530800056

• Nesting properties and anisotropy of the Fermi surface of LuNi2B2C PHYSICAL REVIEW LETTERS Dugdale, S. B., Alam, M. A., Wilkinson, I., Hughes, R. J., Fisher, I. R., Canfield, P. C., Jarlborg, T., Santi, G. 1999; 83 (23): 4824-4827

  View details for Web of Science ID 000084018200038

• Anisotropy and metamagnetism in the RNi2Ge2 (R = Y, La-Nd, Sm-Lu) series JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS Bud'ko, S. L., Islam, Z., Wiener, T. A., Fisher, I. R., Lacerda, A. H., Canfield, P. C. 1999; 205 (1): 53-78

  View details for Web of Science ID 000082380000005

• Systematic study of anisotropic transport and magnetic properties of RAgSb2 (R = Y, La-Nd, Sm, Gd-Tm) JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS Myers, K. D., Bud'ko, S. L., Fisher, I. R., Islam, Z., Kleinke, H., Lacerda, A. H., Canfield, P. C. 1999; 205 (1): 27-52

  View details for Web of Science ID 000082380000004

• On the growth of icosahedral Al-Pd-Mn quasicrystals from the ternary melt PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES Fisher, I. R., Kramer, M. J., Wiener, T. A., Islam, Z., Ross, A. R., Lograsso, T. A., Kracher, A., Goldman, A. I., Canfield, P. C. 1999; 79 (10): 1673-1684

  View details for Web of Science ID 000082940200014

• Critical doping in overdoped high-T-c superconductors: a quantum critical point? International Conference on Solid State Spectroscopy - (ICSSS) Tallon, J. L., Loram, J. W., Williams, G. V., Cooper, J. R., Fisher, I. R., Johnson, J. D., Staines, M. P., Bernhard, C. WILEY-V C H VERLAG GMBH. 1999: 531–40

  View details for Web of Science ID 000082487800087

• Magnetic and transport properties of single-crystal R2Cu2In (R = Gd-Tm, Lu) JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS Fisher, I. R., Islam, Z., Canfield, P. C. 1999; 202 (1): 1-10

  View details for Web of Science ID 000081221300001

• Thermodynamic and transport properties of single-crystal Yb14MnSb11 PHYSICAL REVIEW B Fisher, I. R., Wiener, T. A., Bud'ko, S. L., Canfield, P. C., Chan, J. Y., Kauzlarich, S. M. 1999; 59 (21): 13829-13834

  View details for Web of Science ID 000080778700062

• Systematic studies of the square-hexagonal flux line lattice transition in Lu(Ni1-xCox)(2)B2C: The role of nonlocality PHYSICAL REVIEW LETTERS Gammel, P. L., Bishop, D. J., Eskildsen, M. R., Mortensen, K., Andsersen, N. H., Fisher, I. R., Cheon, K. O., Canfield, P. C., Kogan, V. G. 1999; 82 (20): 4082-4085

  View details for Web of Science ID 000080319900040

• On the growth of decagonal Al-Ni-Co quasicrystals from the ternary melt PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES Fisher, I. R., Kramer, M. J., Islam, Z., Ross, A. R., Kracher, A., Wiener, T., Sailer, M. J., Goldman, A. I., Canfield, P. C. 1999; 79 (3): 425-434

  View details for Web of Science ID 000079085200004

• Boron isotope effect in single-crystal YNi2B2C and LuNi2B2C superconductors PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS Cheon, K. O., Fisher, I. R., Canfield, P. C. 1999; 312 (1-2): 35-39

  View details for Web of Science ID 000078566900005

• Magnetic and transport properties of single-grain R-Mg-Zn icosahedral quasicrystals [R = Y, (Y1-xGdx), (Y1-xTbx), Tb, Dy, Ho, and Er] PHYSICAL REVIEW B Fisher, I. R., Cheon, K. O., Panchula, A. F., Canfield, P. C., Chernikov, M., Ott, H. R., Dennis, K. 1999; 59 (1): 308-321

  View details for Web of Science ID 000077943800068

• Resistivity and magnetic susceptibility of single-crystal Lu(Ni1-xCox)(2)B2C (x=0.0-0.09) PHYSICAL REVIEW B Cheon, K. O., Fisher, I. R., Kogan, V. G., Canfield, P. C., Miranovic, P., Gammel, P. L. 1998; 58 (10): 6463-6467

  View details for Web of Science ID 000076007600074

• Growth of large-grain R-Mg-Zn quasicrystals from the ternary melt (R = Y, Er, Ho, Dy, Tb) PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES Fisher, I. R., Islam, Z., Panchula, A. F., Cheon, K. O., Kramer, M. J., Canfield, P. C., Goldman, A. I. 1998; 77 (6): 1601-1615

  View details for Web of Science ID 000073948900001

• Reinvestigation of long-range magnetic ordering in icosahedral Tb-Mg-Zn PHYSICAL REVIEW B Islam, Z., Fisher, I. R., Zarestky, J., Canfield, P. C., Stassis, C., Goldman, A. I. 1998; 57 (18): R11047-R11050

  View details for Web of Science ID 000073585200008

• Electrical Resistivity of Iodine-Intercalated Bi2Sr2CaCu2O8 Subjected to a Magnetic Field MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS Ghorayeb, A. M., Monnereau, O., Fermond, L., Badeche, T., Hussey, N. E., Dewhurst, C. D., Fisher, I. R., Seow, W. S., Doyle, R. A. 1998; 311: 435-442

  View details for Web of Science ID 000207082400065

• Anisotropic resistivity and normal-state magnetoresistance of RNi2B2C (R = Y, Lu, Er, Ho) PHYSICAL REVIEW B Fisher, I. R., Cooper, J. R., Canfield, P. C. 1997; 56 (17): 10820-10823

  View details for Web of Science ID A1997YD47600032

• Normal-state properties of RNi(2)B(2)C (R=Y,Ho,La) and anisotropic resistivity of single-crystal RNi(2)B(2)C (R=Lu, Pr, Ho) International Conference on Physics and Chemistry of Molecular and Oxide Superconductors Fisher, I. R., Cooper, J. R., Locherer, K. R., Cava, R. J., Canfield, P. C. SPRINGER/PLENUM PUBLISHERS. 1996: 1623–28

  View details for Web of Science ID A1996WC02700090

• Effect of sample density on the resistivity and Hall coefficient of polycrystalline La1.83Sr0.17CuO4 PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS Fisher, I. R., Cooper, J. R. 1996; 272 (1-2): 125-130

  View details for Web of Science ID A1996VZ25900016

• Angular dependence of the c-axis normal state magnetoresistance in single crystal Tl2Ba2CuO6 PHYSICAL REVIEW LETTERS Hussey, N. E., Cooper, J. R., Wheatley, J. M., Fisher, I. R., Carrington, A., Mackenzie, A. P., Lin, C. T., Milat, O. 1996; 76 (1): 122-125

  View details for Web of Science ID A1996TN03700031

• HALL-EFFECT AND THERMOELECTRIC-POWER MEASUREMENTS ON Y0.9CA0.1BA2CU3O7-DELTA International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors IV (M2S-HTSC IV) Fisher, I. R., DESILVA, P. S., Loram, J. W., Tallon, J. L., Carrington, A., Cooper, J. R. ELSEVIER SCIENCE BV. 1994: 1497–1498

  View details for Web of Science ID A1994QC69400388