Arturas Vailionis

All Publications

• Room-Temperature Ferroelectric Epitaxial Nanowire Arrays with Photoluminescence. Nano letters Le, H. K., Zhang, Y., Behera, P., Vailionis, A., Phang, A., Brinn, R. M., Yang, P. 2024

  Abstract

  The development of large-scale, high-quality ferroelectric semiconductor nanowire arrays with interesting light-emitting properties can address limitations in traditional wide-bandgap ferroelectrics, thus serving as building blocks for innovative device architectures and next-generation high-density optoelectronics. Here, we investigate the optical properties of ferroelectric CsGeX3 (X = Br, I) halide perovskite nanowires that are epitaxially grown on muscovite mica substrates by vapor phase deposition. Detailed structural characterizations reveal an incommensurate heteroepitaxial relationship with the mica substrate. Furthermore, photoluminescence that can be tuned from yellow-green to red emissions by varying the halide composition demonstrates that these nanowire networks can serve as platforms for future optoelectronic applications. In addition, the room-temperature ferroelectricity and ferroelectric domain structures of these nanowires are characterized using second harmonic generation (SHG) polarimetry. The combination of room-temperature ferroelectricity with photoluminescence in these nanowire arrays unlocks new avenues for the design of novel multifunctional materials.

  View details for DOI 10.1021/acs.nanolett.4c00453

  View details for PubMedID 38636084

• Author Correction: Ultra-thin lithium aluminate spinel ferrite films with perpendicular magnetic anisotropy and low damping. Nature communications Zheng, X. Y., Channa, S., Riddiford, L. J., Wisser, J. J., Mahalingam, K., Bowers, C. T., McConney, M. E., N'Diaye, A. T., Vailionis, A., Cogulu, E., Ren, H., Galazka, Z., Kent, A. D., Suzuki, Y. 2024; 15 (1): 534

  View details for DOI 10.1038/s41467-023-43051-2

  View details for PubMedID 38225237

  View details for PubMedCentralID PMC10789866

• Teeth Microcracks Research: Towards Multi-Modal Imaging. Bioengineering (Basel, Switzerland) Dumbryte, I., Narbutis, D., Androulidaki, M., Vailionis, A., Juodkazis, S., Malinauskas, M. 2023; 10 (12)

  Abstract

  This perspective is an overview of the recent advances in teeth microcrack (MC) research, where there is a clear tendency towards a shift from two-dimensional (2D) to three-dimensional (3D) examination techniques, enhanced with artificial intelligence models for data processing and image acquisition. X-ray micro-computed tomography combined with machine learning allows 3D characterization of all spatially resolved cracks, despite the locations within the tooth in which they begin and extend, and the arrangement of MCs and their structural properties. With photoluminescence and micro-/nano-Raman spectroscopy, optical properties and chemical and elemental composition of the material can be evaluated, thus helping to assess the structural integrity of the tooth at the MC site. Approaching tooth samples having cracks from different perspectives and using complementary laboratory techniques, there is a natural progression from 3D to multi-modal imaging, where the volumetric (passive: dimensions) information of the tooth sample can be supplemented by dynamic (active: composition, interaction) image data. Revelation of tooth cracks clearly shows the need to re-assess the role of these MCs and their effect on the structural integrity and longevity of the tooth. This provides insight into the nature of cracks in natural hard materials and contributes to a better understanding of how bio-inspired structures could be designed to foresee crack propagation in biosolids.

  View details for DOI 10.3390/bioengineering10121354

  View details for PubMedID 38135945

  View details for PubMedCentralID PMC10740647

• Correlating chemistry and mass transport in sustainable iron production. Proceedings of the National Academy of Sciences of the United States of America Zheng, X., Paul, S., Moghimi, L., Wang, Y., Vilá, R. A., Zhang, F., Gao, X., Deng, J., Jiang, Y., Xiao, X., Wu, C., Greenburg, L. C., Yang, Y., Cui, Y., Vailionis, A., Kuzmenko, I., Llavsky, J., Yin, Y., Cui, Y., Dresselhaus-Marais, L. 2023; 120 (43): e2305097120

  Abstract

  Steelmaking contributes 8% to the total CO2 emissions globally, primarily due to coal-based iron ore reduction. Clean hydrogen-based ironmaking has variable performance because the dominant gas-solid reduction mechanism is set by the defects and pores inside the mm- to nm-sized oxide particles that change significantly as the reaction progresses. While these governing dynamics are essential to establish continuous flow of iron and its ores through reactors, the direct link between agglomeration and chemistry is still contested due to missing measurements. In this work, we directly measure the connection between chemistry and agglomeration in the smallest iron oxides relevant to magnetite ores. Using synthesized spherical 10-nm magnetite particles reacting in H2, we resolve the formation and consumption of wüstite (Fe1-xO)-the step most commonly attributed to whiskering. Using X-ray diffraction, we resolve crystallographic anisotropy in the rate of the initial reaction. Complementary imaging demonstrated how the particles self-assemble, subsequently react, and grow into elongated "whisker" structures. Our insights into how morphologically uniform iron oxide particles react and agglomerate in H2 reduction enable future size-dependent models to effectively describe the multiscale aspects of iron ore reduction.

  View details for DOI 10.1073/pnas.2305097120

  View details for PubMedID 37847734

• Aluminum substitution in low damping epitaxial lithium ferrite films APPLIED PHYSICS LETTERS O'Mahoney, D., Channa, S., Zheng, X., Vailionis, A., Shafer, P., N'Diaye, A. T., Klewe, C., Suzuki, Y. 2023; 123 (17)

  View details for DOI 10.1063/5.0163362

  View details for Web of Science ID 001095984400005

• Enhanced functionality of Scots pine sapwood by in situ hydrothermal synthesis of GdPO4•H2O:Eu3+Composites in woods matrix CERAMICS INTERNATIONAL Baublyte, M., Vailionis, A., Sokol, D., Skaudzius, R. 2023; 49 (19): 31255-31264

  View details for DOI 10.1016/j.ceramint.2023.07.073

  View details for Web of Science ID 001150125900001

• Low-temperature carbon dioxide conversion via reverse water-gas shift thermochemical looping with supported iron oxide CELL REPORTS PHYSICAL SCIENCE Sun, E., Wan, G., Haribal, V., Gigantino, M., Marin-Quiros, S., Oh, J., Vailionis, A., Tong, A., Randall, R., Rojas, J., Gupta, R., Majumdar, A. 2023; 4 (9)

  View details for DOI 10.1016/j.xcrp.2023.101581

  View details for Web of Science ID 001083119200001

• Ultra-thin lithium aluminate spinel ferrite films with perpendicular magnetic anisotropy and low damping. Nature communications Zheng, X. Y., Channa, S., Riddiford, L. J., Wisser, J. J., Mahalingam, K., Bowers, C. T., McConney, M. E., N'Diaye, A. T., Vailionis, A., Cogulu, E., Ren, H., Galazka, Z., Kent, A. D., Suzuki, Y. 2023; 14 (1): 4918

  Abstract

  Ultra-thin films of low damping ferromagnetic insulators with perpendicular magnetic anisotropy have been identified as critical to advancing spin-based electronics by significantly reducing the threshold for current-induced magnetization switching while enabling new types of hybrid structures or devices. Here, we have developed a new class of ultra-thin spinel structure Li0.5Al1.0Fe1.5O4 (LAFO) films on MgGa2O4 (MGO) substrates with: 1) perpendicular magnetic anisotropy; 2) low magnetic damping and 3) the absence of degraded or magnetic dead layers. These films have been integrated with epitaxial Pt spin source layers to demonstrate record low magnetization switching currents and high spin-orbit torque efficiencies. These LAFO films on MGO thus combine all of the desirable properties of ferromagnetic insulators with perpendicular magnetic anisotropy, opening new possibilities for spin based electronics.

  View details for DOI 10.1038/s41467-023-40733-9

  View details for PubMedID 37582804

  View details for PubMedCentralID PMC10427713

• Quantification of strain and its impact on the phase stabilization of all-inorganic cesium lead iodide perovskites MATTER Le, H. D., Lin, C., Jin, J., Zhang, Y., Lin, Z., Vailionis, A., Tamura, N., Yang, P. 2023; 6 (7): 2368-2382

  View details for DOI 10.1016/j.matt.2023.05.027

  View details for Web of Science ID 001061843200001

• Field-free spin-orbit torque switching assisted by in-plane unconventional spin torque in ultrathin [Pt/Co]N. Nature communications Xue, F., Lin, S. J., Song, M., Hwang, W., Klewe, C., Lee, C. M., Turgut, E., Shafer, P., Vailionis, A., Huang, Y. L., Tsai, W., Bao, X., Wang, S. X. 2023; 14 (1): 3932

  Abstract

  Electrical manipulation of magnetization without an external magnetic field is critical for the development of advanced non-volatile magnetic-memory technology that can achieve high memory density and low energy consumption. Several recent studies have revealed efficient out-of-plane spin-orbit torques (SOTs) in a variety of materials for field-free type-z SOT switching. Here, we report on the corresponding type-x configuration, showing significant in-plane unconventional spin polarizations from sputtered ultrathin [Pt/Co]N, which are either highly textured on single crystalline MgO substrates or randomly textured on SiO2 coated Si substrates. The unconventional spin currents generated in the low-dimensional Co films result from the strong orbital magnetic moment, which has been observed by X-ray magnetic circular dichroism (XMCD) measurement. The x-polarized spin torque efficiency reaches up to -0.083 and favors complete field-free switching of CoFeB magnetized along the in-plane charge current direction. Micromagnetic simulations additionally demonstrate its lower switching current than type-y switching, especially in narrow current pulses. Our work provides additional pathways for electrical manipulation of spintronic devices in the pursuit of high-speed, high-density, and low-energy non-volatile memory.

  View details for DOI 10.1038/s41467-023-39649-1

  View details for PubMedID 37402728

• Structure and Optical Anisotropy of Spider Scales and Silk: The Use of Chromaticity and Azimuth Colors to Optically Characterize Complex Biological Structures. Nanomaterials (Basel, Switzerland) Linklater, D., Vailionis, A., Ryu, M., Kamegaki, S., Morikawa, J., Mu, H., Smith, D., Maasoumi, P., Ford, R., Katkus, T., Blamires, S., Kondo, T., Nishijima, Y., Moraru, D., Shribak, M., O'Connor, A., Ivanova, E. P., Ng, S. H., Masuda, H., Juodkazis, S. 2023; 13 (12)

  Abstract

  Herein, we give an overview of several less explored structural and optical characterization techniques useful for biomaterials. New insights into the structure of natural fibers such as spider silk can be gained with minimal sample preparation. Electromagnetic radiation (EMR) over a broad range of wavelengths (from X-ray to THz) provides information of the structure of the material at correspondingly different length scales (nm-to-mm). When the sample features, such as the alignment of certain fibers, cannot be characterized optically, polarization analysis of the optical images can provide further information on feature alignment. The 3D complexity of biological samples necessitates that there be feature measurements and characterization over a large range of length scales. We discuss the issue of characterizing complex shapes by analysis of the link between the color and structure of spider scales and silk. For example, it is shown that the green-blue color of a spider scale is dominated by the chitin slab's Fabry-Perot-type reflectivity rather than the surface nanostructure. The use of a chromaticity plot simplifies complex spectra and enables quantification of the apparent colors. All the experimental data presented herein are used to support the discussion on the structure-color link in the characterization of materials.

  View details for DOI 10.3390/nano13121894

  View details for PubMedID 37368324

• Observation of anti-damping spin-orbit torques generated by in-plane and out-of-plane spin polarizations in MnPd3. Nature materials Dc, M., Shao, D. F., Hou, V. D., Vailionis, A., Quarterman, P., Habiboglu, A., Venuti, M. B., Xue, F., Huang, Y. L., Lee, C. M., Miura, M., Kirby, B., Bi, C., Li, X., Deng, Y., Lin, S. J., Tsai, W., Eley, S., Wang, W. G., Borchers, J. A., Tsymbal, E. Y., Wang, S. X. 2023

  Abstract

  Large spin-orbit torques (SOTs) generated by topological materials and heavy metals interfaced with ferromagnets are promising for next-generation magnetic memory and logic devices. SOTs generated from y spin originating from spin Hall and Edelstein effects can realize field-free magnetization switching only when the magnetization and spin are collinear. Here we circumvent the above limitation by utilizing unconventional spins generated in a MnPd3 thin film grown on an oxidized silicon substrate. We observe conventional SOT due to y spin, and out-of-plane and in-plane anti-damping-like torques originated from z spin and x spin, respectively, in MnPd3/CoFeB heterostructures. Notably, we have demonstrated complete field-free switching of perpendicular cobalt via out-of-plane anti-damping-like SOT. Density functional theory calculations show that the observed unconventional torques are due to the low symmetry of the (114)-oriented MnPd3 films. Altogether our results provide a path toward realization of a practical spin channel in ultrafast magnetic memory and logic devices.

  View details for DOI 10.1038/s41563-023-01522-3

  View details for PubMedID 37012436

• Large Spin-Orbit-Torque Efficiency and Room-Temperature Magnetization Switching in SrIrO3/Co-Fe-B Heterostructures PHYSICAL REVIEW APPLIED Li, P., Channa, S., Li, X., Alahmed, L., Tang, C., Yi, D., Riddiford, L., Wisser, J., Balakrishnan, P. P., Zheng, X., Lu, D., Vailionis, A., Wang, S. X., Suzuki, Y. 2023; 23 (2)

  View details for DOI 10.1103/PhysRevApplied.19.024076

  View details for Web of Science ID 000943193100001

• Investigation of the Antimicrobial Properties of Beetroot-Gelatin Films Containing Silver Particles Obtained via Green Synthesis APPLIED SCIENCES-BASEL Puiso, J., Adliene, D., Paskevicius, A., Vailionis, A. 2023; 13 (3)

  View details for DOI 10.3390/app13031926

  View details for Web of Science ID 000929276300001

• Revelation of microcracks as tooth structural element by X-ray tomography and machine learning. Scientific reports Dumbryte, I., Narbutis, D., Vailionis, A., Juodkazis, S., Malinauskas, M. 2022; 12 (1): 22489

  Abstract

  Although teeth microcracks (MCs) have long been considered more of an aesthetic problem, their exact role in the structure of a tooth and impact on its functionality is still unknown. The aim of this study was to reveal the possibilities of an X-ray micro-computed tomography ([Formula: see text]CT) in combination with convolutional neural network (CNN) assisted voxel classification and volume segmentation for three-dimensional (3D) qualitative analysis of tooth microstructure and verify this approach with four extracted human premolars. Samples were scanned using a [Formula: see text]CT instrument (Xradia 520 Versa; ZEISS) and segmented with CNN to identify enamel, dentin, and cracks. A new CNN image segmentation model was trained based on "Multiclass semantic segmentation using DeepLabV3+" example and was implemented with "TensorFlow". The technique which was used allowed 3D characterization of all MCs of a tooth, regardless of the volume of the tooth in which they begin and extend, and the evaluation of the arrangement of cracks and their structural features. The proposed method revealed an intricate star-shaped network of MCs covering most of the inner tooth, and the main crack planes in all samples were arranged radially in two almost perpendicular directions, suggesting that the cracks could be considered as a planar structure.

  View details for DOI 10.1038/s41598-022-27062-5

  View details for PubMedID 36577779

• Strain engineering during epitaxial growth of oxides Epitaxial Growth of Complex Metal Oxides Vailionis, A. Woodhead Publishing. 2022; 2nd: 159

  View details for DOI https://doi.org/10.1016/C2018-0-02659-6

• Three-dimensional non-destructive visualization of teeth enamel microcracks using X-ray micro-computed tomography. Scientific reports Dumbryte, I., Vailionis, A., Skliutas, E., Juodkazis, S., Malinauskas, M. 2021; 11 (1): 14810

  Abstract

  Although the topic of tooth fractures has been extensively analyzed in the dental literature, there is still insufficient information about the potential effect of enamel microcracks (EMCs) on the underlying tooth structures. For a precise examination of the extent of the damage to the tooth structure in the area of EMCs, it is necessary to carry out their volumetric [(three-dimensional (3D)] evaluation. The aim of this study was to validate an X-ray micro-computed tomography ([Formula: see text]CT) as a technique suitable for 3D non-destructive visualization and qualitative analysis of teeth EMCs of different severity. Extracted human maxillary premolars were examined using a [Formula: see text]CT instrument ZEISS Xradia 520 Versa. In order to separate crack, dentin, and enamel volumes a Deep Learning (DL) algorithm, part of the Dragonfly's segmentation toolkit, was utilized. For segmentation needs we implemented Dragonfly's pre-built UNet neural network. The scanning technique which was used made it possible to recognize and detect not only EMCs that are visible on the outer surface but also those that are buried deep inside the tooth. The 3D visualization, combined with DL assisted segmentation, enabled the evaluation of the dynamics of an EMC and precise examination of its position with respect to the dentin-enamel junction.

  View details for DOI 10.1038/s41598-021-94303-4

  View details for PubMedID 34285299

• Charge-spin interconversion in epitaxial Pt probed by spin-orbit torques in a magnetic insulator PHYSICAL REVIEW MATERIALS Li, P., Riddiford, L. J., Bi, C., Wisser, J. J., Sun, X., Vailionis, A., Veit, M. J., Altman, A., Li, X., Mahendra, D. C., Wang, S. X., Suzuki, Y., Emori, S. 2021; 5 (6)

  View details for DOI 10.1103/PhysRevMaterials.5.064404

  View details for Web of Science ID 000661932200002

• Emergent long-range magnetic order in ultrathin (111)-oriented LaNiO3 films NPJ QUANTUM MATERIALS Kane, M. M., Vailionis, A., Riddiford, L. J., Mehta, A., N'Diaye, A. T., Klewe, C., Shafer, P., Arenholz, E., Suzuki, Y. 2021; 6 (1)

  View details for DOI 10.1038/s41535-021-00345-2

  View details for Web of Science ID 000656948700001

• Three-Dimensional Analysis of Particle Distribution on Filter Layers inside N95 Respirators by Deep Learning. Nano letters Lee, H. R., Liao, L., Xiao, W., Vailionis, A., Ricco, A. J., White, R., Nishi, Y., Chiu, W., Chu, S., Cui, Y. 2020

  Abstract

  The global COVID-19 pandemic has changed many aspects of daily lives. Wearing personal protective equipment, especially respirators (face masks), has become common for both the public and medical professionals, proving to be effective in preventing spread of the virus. Nevertheless, a detailed understanding of respirator filtration-layer internal structures and their physical configurations is lacking. Here, we report three-dimensional (3D) internal analysis of N95 filtration layers via X-ray tomography. Using deep learning methods, we uncover how the distribution and diameters of fibers within these layers directly affect contaminant particle filtration. The average porosity of the filter layers is found to be 89.1%. Contaminants are more efficiently captured by denser fiber regions, with fibers <1.8 mum in diameter being particularly effective, presumably because of the stronger electric field gradient on smaller diameter fibers. This study provides critical information for further development of N95-type respirators that combine high efficiency with good breathability.

  View details for DOI 10.1021/acs.nanolett.0c04230

  View details for PubMedID 33283521

• Two-dimensional electron systems in perovskite oxide heterostructures: Role of the polarity-induced substitutional defects PHYSICAL REVIEW MATERIALS Lin, S., Kuo, C., Shao, Y., Chuang, Y., Geessinck, J., Huijben, M., Rueff, J., Graff, I. L., Conti, G., Peng, Y., Bostwick, A., Gullikson, E., Gullikson, E., Nemsak, S., Vailionis, A., Gauquelin, N., Verbeeck, J., Ghiringhelli, G., Schneider, C. M., Fadley, C. S. 2020; 4 (11)

  View details for DOI 10.1103/PhysRevMaterials.4.115002

  View details for Web of Science ID 000592432200004

• Extreme tensile strain states in La0.7Ca0.3MnO3 membranes. Science (New York, N.Y.) Hong, S. S., Gu, M. n., Verma, M. n., Harbola, V. n., Wang, B. Y., Lu, D. n., Vailionis, A. n., Hikita, Y. n., Pentcheva, R. n., Rondinelli, J. M., Hwang, H. Y. 2020; 368 (6486): 71–76

  Abstract

  A defining feature of emergent phenomena in complex oxides is the competition and cooperation between ground states. In manganites, the balance between metallic and insulating phases can be tuned by the lattice; extending the range of lattice control would enhance the ability to access other phases. We stabilized uniform extreme tensile strain in nanoscale La0.7Ca0.3MnO3 membranes, exceeding 8% uniaxially and 5% biaxially. Uniaxial and biaxial strain suppresses the ferromagnetic metal at distinctly different strain values, inducing an insulator that can be extinguished by a magnetic field. Electronic structure calculations indicate that the insulator consists of charge-ordered Mn4+ and Mn3+ with staggered strain-enhanced Jahn-Teller distortions within the plane. This highly tunable strained membrane approach provides a broad opportunity to design and manipulate correlated electron states.

  View details for DOI 10.1126/science.aax9753

  View details for PubMedID 32241944

• Modification of spin-ice physics in Ho2Ti2O7 thin films PHYSICAL REVIEW MATERIALS Barry, K., Zhang, B., Anand, N., Xing, Y., Vailionis, A., Neu, J., Heikes, C., Cochran, C., Zhou, H., Qiu, Y., Ratcliff, W., Siegrist, T., Beekman, C. 2019; 3 (8)

  View details for DOI 10.1103/PhysRevMaterials.3.084412

  View details for Web of Science ID 000481473800002

• Nanoscale optical and structural characterisation of silk. Beilstein journal of nanotechnology Ryu, M., Honda, R., Cernescu, A., Vailionis, A., Balčytis, A., Vongsvivut, J., Li, J. L., Linklater, D. P., Ivanova, E. P., Mizeikis, V., Tobin, M. J., Morikawa, J., Juodkazis, S. 2019; 10: 922-929

  Abstract

  The nanoscale composition of silk defining its unique properties via a hierarchial structural anisotropy needs to be analysed at the highest spatial resolution of tens of nanometers corresponding to the size of fibrils made of β-sheets, which are the crystalline building blocks of silk. Nanoscale optical and structural properties of silk have been measured from 100 nm thick longitudinal slices of silk fibers with ca. 10 nm resolution, the highest so far. Optical sub-wavelength resolution in hyperspectral mapping of absorbance and molecular orientation were carried out for comparison at IR wavelengths of 2-10 μm using synchrotron radiation. A reliable distinction of transmission changes by only 1-2% as the anisotropy of amide bands was obtained from nanometer-thin slices of silk.

  View details for DOI 10.3762/bjnano.10.93

  View details for PubMedID 31165019

  View details for PubMedCentralID PMC6541335

• Nanoscale optical and structural characterisation of silk BEILSTEIN JOURNAL OF NANOTECHNOLOGY Ryu, M., Handa, R., Cernescu, A., Vailionis, A., Balcytis, A., Vongsvivut, J., Li, J., Linklater, D. P., Ivanova, E. P., Mizeikis, V., Tobin, M. J., Morikawa, J., Juodkazis, S. 2019; 10: 922–29

  View details for DOI 10.3762/bjnano.10.93

  View details for Web of Science ID 000465334300001

• Modification of spin-ice physics in Ho2Ti2O7 thin films. Physical review materials Barry, K., Zhang, B., Anand, N., Xin, Y., Vailionis, A., Neu, J., Heikes, C., Cochran, C., Zhou, H., Qiu, Y., Ratcliff, W., Siegrist, T., Beekman, C. 2019; 3

  Abstract

  We present an extensive study on the effect of substrate orientation, strain, stoichiometry, and defects on spin-ice physics in Ho2Ti2O7 thin films grown onto yttria-stabilized-zirconia substrates. We find that growth in different orientations produces different strain states in the films. All films exhibit similar c-axis lattice parameters for their relaxed portions, which are consistently larger than the bulk value of 10.1 Å. Transmission electron microscopy reveals antisite disorder and growth defects to be present in the films, but evidence of stuffing is not observed. The amount of disorder depends on the growth orientation, with the (110) film showing the least. Magnetization measurements at 1.8 K show the expected magnetic anisotropy and saturation magnetization values associated with a spin ice for all orientations; shape anisotropy is apparent when comparing in- and out-of-plane directions. Significantly, only the (110)-oriented films display the hallmark spin-ice plateau state in magnetization, albeit less well defined compared to the plateau observed in a single crystal. Neutron-scattering maps on the more disordered (111)-oriented films show the Q=0 phase previously observed in bulk materials, but the Q=X phase giving the plateau state remains elusive. We conclude that the spin-ice physics in thin films is modified by defects and strain, leading to a reduction in the temperature at which correlations drive the system into the spin-ice state.

  View details for DOI 10.1103/physrevmaterials.3.084412

  View details for PubMedID 38617995

  View details for PubMedCentralID PMC11015469

• Depth-resolved resonant inelastic x-ray scattering at a superconductor/half-metallic-ferromagnet interface through standing wave excitation PHYSICAL REVIEW B Kuo, C., Lin, S., Ghiringhelli, G., Peng, Y., De Luca, G., Di Castro, D., Betto, D., Gehlmann, M., Wijnands, T., Huijben, M., Meyer-Ilse, J., Gullikson, E., Kortright, J. B., Vailionis, A., Gauquelin, N., Verbeeck, J., Gerber, T., Balestrino, G., Brookes, N. B., Braicovich, L., Fadley, C. S. 2018; 98 (23)

  View details for DOI 10.1103/PhysRevB.98.235146

  View details for Web of Science ID 000454160800004

• Strain Tuning in Complex Oxide Epitaxial Films Using an Ultrathin Strontium Aluminate Buffer Layer PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS Lu, D., Hikita, Y., Baek, D. J., Merz, T. A., Sato, H., Kim, B., Yajima, T., Bell, C., Vailionis, A., Kourkoutis, L. F., Hwang, H. Y. 2018; 12 (3)

  View details for DOI 10.1002/pssr.201700339

  View details for Web of Science ID 000426745100002

• Robust Pinhole-free Li3N Solid Electrolyte Grown from Molten Lithium. ACS central science Li, Y., Sun, Y., Pei, A., Chen, K., Vailionis, A., Li, Y., Zheng, G., Sun, J., Cui, Y. 2018; 4 (1): 97–104

  Abstract

  Lithium metal is the ultimate anode choice for high energy density rechargeable lithium batteries. However, it suffers from inferior electrochemical performance and safety issues due to its high reactivity and the growth of lithium dendrites. It has long been desired to develop a materials coating on Li metal, which is pinhole-free, mechanically robust without fracture during Li metal deposition and stripping, and chemically stable against Li metal and liquid electrolytes, all while maintaining adequate ionic conductivity. However, such an ideal material coating has yet to be found. Here we report a novel synthesis method by reacting clean molten lithium foil directly with pure nitrogen gas to generate instantaneously a pinhole-free and ionically conductive alpha-Li3N film directly bonded onto Li metal foil. The film consists of highly textured large Li3N grains (tens of mum) with (001) crystalline planes parallel to the Li metal surface. The bonding between textured grains is strong, resulting in a mechanically robust film which does not crack even when bent to a 0.8 cm curvature radius and is found to maintain pinhole-free coverage during Li metal deposition and stripping. The measured ionic conductivity is up to 5.2 * 10-4 S cm-1, sufficient for maintaining regular current densities for controllable film thicknesses ranging from 2 to 30 mum. This Li3N coating is chemically stable, isolating the reactive metallic lithium from liquid electrolyte, prevents continuous electrolyte consumption during battery cycling, and promotes dendrite-free uniform lithium plating/stripping underneath. We demonstrated Li|Li4Ti5O12 cells with stable and flat potential profiles for 500 cycles without capacity decay or an increase in potential hysteresis.

  View details for PubMedID 29392181

• Strong texturing of lithium metal in batteries PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Shi, F., Pei, A., Vailionis, A., Xie, J., Liu, B., Zhao, J., Gong, Y., Cui, Y. 2017; 114 (46): 12138–43

  Abstract

  Lithium, with its high theoretical specific capacity and lowest electrochemical potential, has been recognized as the ultimate negative electrode material for next-generation lithium-based high-energy-density batteries. However, a key challenge that has yet to be overcome is the inferior reversibility of Li plating and stripping, typically thought to be related to the uncontrollable morphology evolution of the Li anode during cycling. Here we show that Li-metal texturing (preferential crystallographic orientation) occurs during electrochemical deposition, which governs the morphological change of the Li anode. X-ray diffraction pole-figure analysis demonstrates that the texture of Li deposits is primarily dependent on the type of additive or cross-over molecule from the cathode side. With adsorbed additives, like LiNO3 and polysulfide, the lithium deposits are strongly textured, with Li (110) planes parallel to the substrate, and thus exhibit uniform, rounded morphology. A growth diagram of lithium deposits is given to connect various texture and morphology scenarios for different battery electrolytes. This understanding of lithium electrocrystallization from the crystallographic point of view provides significant insight for future lithium anode materials design in high-energy-density batteries.

  View details for PubMedID 29087316

• 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

• : Controlling selectivity toward oxygenates and hydrocarbons. Proceedings of the National Academy of Sciences of the United States of America Hahn, C., Hatsukade, T., Kim, Y., Vailionis, A., Baricuatro, J. H., Higgins, D. C., Nitopi, S. A., Soriaga, M. P., Jaramillo, T. F. 2017; 114 (23): 5918-5923

  Abstract

  In this study we control the surface structure of Cu thin-film catalysts to probe the relationship between active sites and catalytic activity for the electroreduction of CO2 to fuels and chemicals. Here, we report physical vapor deposition of Cu thin films on large-format (∼6 cm(2)) single-crystal substrates, and confirm epitaxial growth in the <100>, <111>, and <751> orientations using X-ray pole figures. To understand the relationship between the bulk and surface structures, in situ electrochemical scanning tunneling microscopy was conducted on Cu(100), (111), and (751) thin films. The studies revealed that Cu(100) and (111) have surface adlattices that are identical to the bulk structure, and that Cu(751) has a heterogeneous kinked surface with (110) terraces that is closely related to the bulk structure. Electrochemical CO2 reduction testing showed that whereas both Cu(100) and (751) thin films are more active and selective for C-C coupling than Cu(111), Cu(751) is the most selective for >2e(-) oxygenate formation at low overpotentials. Our results demonstrate that epitaxy can be used to grow single-crystal analogous materials as large-format electrodes that provide insights on controlling electrocatalytic activity and selectivity for this reaction.

  View details for DOI 10.1073/pnas.1618935114

  View details for PubMedID 28533377

• Hybrid metal-organic chalcogenide nanowires with electrically conductive inorganic core through diamondoid-directed assembly. Nature materials Yan, H., Hohman, J. N., Li, F. H., Jia, C., Solis-Ibarra, D., Wu, B., Dahl, J. E., Carlson, R. M., Tkachenko, B. A., Fokin, A. A., Schreiner, P. R., Vailionis, A., Kim, T. R., Devereaux, T. P., Shen, Z., Melosh, N. A. 2017; 16 (3): 349-355

  Abstract

  Controlling inorganic structure and dimensionality through structure-directing agents is a versatile approach for new materials synthesis that has been used extensively for metal-organic frameworks and coordination polymers. However, the lack of 'solid' inorganic cores requires charge transport through single-atom chains and/or organic groups, limiting their electronic properties. Here, we report that strongly interacting diamondoid structure-directing agents guide the growth of hybrid metal-organic chalcogenide nanowires with solid inorganic cores having three-atom cross-sections, representing the smallest possible nanowires. The strong van der Waals attraction between diamondoids overcomes steric repulsion leading to a cis configuration at the active growth front, enabling face-on addition of precursors for nanowire elongation. These nanowires have band-like electronic properties, low effective carrier masses and three orders-of-magnitude conductivity modulation by hole doping. This discovery highlights a previously unexplored regime of structure-directing agents compared with traditional surfactant, block copolymer or metal-organic framework linkers.

  View details for DOI 10.1038/nmat4823

  View details for PubMedID 28024157

• Variation in superconducting transition temperature due to tetragonal domains in two-dimensionally doped SrTiO3 PHYSICAL REVIEW B Noad, H., Spanton, E. M., Nowack, K. C., Inoue, H., Kim, M., Merz, T. A., Bell, C., Hikita, Y., Xu, R., Liu, W., Vailionis, A., Hwang, H. Y., Moler, K. A. 2016; 94 (17)

  View details for DOI 10.1103/PhysRevB.94.174516

  View details for Web of Science ID 000388815300010

• Ultrafast terahertz-field-driven ionic response in ferroelectric BaTiO3 PHYSICAL REVIEW B Chen, F., Zhu, Y., Liu, S., Qi, Y., Hwang, H. Y., Brandt, N. C., Lu, J., QUIRIN, F., Enquist, H., Zalden, P., Hu, T., Goodfellow, J., Sher, M., Hoffmann, M. C., Zhu, D., Lemke, H., Glownia, J., Chollet, M., Damodaran, A. R., Park, J., Cai, Z., Jung, I. W., Highland, M. J., Walko, D. A., Freeland, J. W., Evans, P. G., Vailionis, A., Larsson, J., Nelson, K. A., Rappe, A. M., Sokolowski-Tinten, K., Martin, L. W., Wen, H., Lindenberg, A. M. 2016; 94 (18)

  View details for DOI 10.1103/PhysRevB.94.180104

  View details for Web of Science ID 000388465200001

• Interfacial Symmetry Control of Emergent Ferromagnetism at the Nanoscale. Nano letters Grutter, A. J., Vailionis, A., Borchers, J. A., Kirby, B. J., Flint, C. L., He, C., Arenholz, E., Suzuki, Y. 2016; 16 (9): 5647-5651

  Abstract

  The emergence of complex new ground states at interfaces has been identified as one of the most promising routes to highly tunable nanoscale materials. Despite recent progress, isolating and controlling the underlying mechanisms behind these emergent properties remains among the most challenging materials physics problems to date. In particular, generating ferromagnetism localized at the interface of two nonferromagnetic materials is of fundamental and technological interest. Moreover, the ability to turn the ferromagnetism on and off would shed light on the origin of such emergent phenomena and is promising for spintronic applications. We demonstrate that ferromagnetism confined within one unit cell at the interface of CaRuO3 and CaMnO3 can be switched on and off by changing the symmetry of the oxygen octahedra connectivity at the boundary. Interfaces that are symmetry-matched across the boundary exhibit interfacial CaMnO3 ferromagnetism while the ferromagnetism at symmetry-mismatched interfaces is suppressed. We attribute the suppression of ferromagnetic order to a reduction in charge transfer at symmetry-mismatched interfaces, where frustrated bonding weakens the orbital overlap. Thus, interfacial symmetry is a new route to control emergent ferromagnetism in materials such as CaMnO3 that exhibit antiferromagnetism in bulk form.

  View details for DOI 10.1021/acs.nanolett.6b02255

  View details for PubMedID 27472285

• Depth resolved domain mapping in tetragonal SrTiO3 by micro-Laue diffraction APPLIED PHYSICS LETTERS Merz, T. A., Noad, H., Xu, R., Inoue, H., Liu, W., Hikita, Y., Vailionis, A., Moler, K. A., Hwang, H. Y. 2016; 108 (18)

  View details for DOI 10.1063/1.4948351

  View details for Web of Science ID 000377023300026

• Massive Dirac Fermion Observed in Lanthanide-Doped Topological Insulator Thin Films SCIENTIFIC REPORTS Harrison, S. E., Collins-McIntyre, L. J., Schoenherr, P., Vailionis, A., Srot, V., van Aken, P. A., Kellock, A. J., Pushp, A., Parkin, S. S., Harris, J. S., Zhou, B., Chen, Y. L., Hesjedal, T. 2015; 5

  Abstract

  The breaking of time reversal symmetry (TRS) in three-dimensional (3D) topological insulators (TIs), and thus the opening of a 'Dirac-mass gap' in the linearly dispersed Dirac surface state, is a prerequisite for unlocking exotic physical states. Introducing ferromagnetic long-range order by transition metal doping has been shown to break TRS. Here, we present the study of lanthanide (Ln) doped Bi2Te3, where the magnetic doping with high-moment lanthanides promises large energy gaps. Using molecular beam epitaxy, single-crystalline, rhombohedral thin films with Ln concentrations of up to ~35%, substituting on Bi sites, were achieved for Dy, Gd, and Ho doping. Angle-resolved photoemission spectroscopy shows the characteristic Dirac cone for Gd and Ho doping. In contrast, for Dy doping above a critical doping concentration, a gap opening is observed via the decreased spectral intensity at the Dirac point, indicating a topological quantum phase transition persisting up to room-temperature.

  View details for DOI 10.1038/srep15767

  View details for Web of Science ID 000363453000001

  View details for PubMedID 26503435

  View details for PubMedCentralID PMC4621505

• Imaging and control of ferromagnetism in LaMnO3/SrTiO3 heterostructures SCIENCE Wang, X. R., Li, C. J., Lu, W. M., Paudel, T. R., Leusink, D. P., Hoek, M., Poccia, N., Vailionis, A., Venkatesan, T., Coey, J. M., Tsymbal, E. Y., Ariando, Hilgenkamp, H. 2015; 349 (6249): 716-719

  Abstract

  Oxide heterostructures often exhibit unusual physical properties that are absent in the constituent bulk materials. Here, we report an atomically sharp transition to a ferromagnetic phase when polar antiferromagnetic LaMnO3 (001) films are grown on SrTiO3 substrates. For a thickness of six unit cells or more, the LaMnO3 film abruptly becomes ferromagnetic over its entire area, which is visualized by scanning superconducting quantum interference device microscopy. The transition is explained in terms of electronic reconstruction originating from the polar nature of the LaMnO3 (001) films. Our results demonstrate that functionalities can be engineered in oxide films that are only a few atomic layers thick.

  View details for DOI 10.1126/science.aaa5198

  View details for Web of Science ID 000359415100031

  View details for PubMedID 26273050

• Research Update: Stoichiometry controlled oxide thin film growth by pulsed laser deposition APL MATERIALS Groenen, R., Smit, J., Orsel, K., Vailionis, A., Bastiaens, B., Huijben, M., Boller, K., Rijnders, G., Koster, G. 2015; 3 (7)

  View details for DOI 10.1063/1.4926933

  View details for Web of Science ID 000358923500001

• The effects of strain on crystal structure and properties during epitaxial growth of oxides Epitaxial Growth of Complex Metal Oxides Huijben, M., Rijnders, G. edited by Koster, G. Woodhead Publishing. 2015

  View details for DOI doi.org/10.1016/B978-1-78242-245-7.00007-5

• The application of floating dies for high speed growth of CsI single crystals by edge-defined film-fed growth (EFG) JOURNAL OF CRYSTAL GROWTH Guguschev, C., Calvert, G., Podowitz, S., Vailionis, A., Yeckel, A., Feigelson, R. S. 2014; 404: 231-240

  View details for DOI 10.1016/j.jcrysgro.2014.05.031

  View details for Web of Science ID 000341414600038

• Symmetry and lattice mismatch induced strain accommodation near and away from correlated perovskite interfaces APPLIED PHYSICS LETTERS Vailionis, A., Boschker, H., Liao, Z., Smit, J. R., Rijnders, G., Huijben, M., Koster, G. 2014; 105 (13)

  View details for DOI 10.1063/1.4896969

  View details for Web of Science ID 000343031700022

• Phase Transformation in Laser-Induced Micro-Explosion in Olivine (Fe,Mg)(2)SiO4 ADVANCED ENGINEERING MATERIALS Buividas, R., Gervinskas, G., Tadich, A., Cowie, B. C., Mizeikis, V., Vailionis, A., de Ligny, D., Gamaly, E. G., Rode, A. V., Juodkazis, S. 2014; 16 (6): 767-773

  View details for DOI 10.1002/adem.201400091

  View details for Web of Science ID 000337635500013

• Controlling the Structural and Optical Properties of Ta3N5 Films through Nitridation Temperature and the Nature of the Ta Metal CHEMISTRY OF MATERIALS Pinaud, B. A., Vailionis, A., Jaramillo, T. F. 2014; 26 (4): 1576-1582

  View details for DOI 10.1021/cm403482s

  View details for Web of Science ID 000332059400012

• Stabilization of spin-zero Ru4+ through epitaxial strain in SrRuO3 thin films PHYSICAL REVIEW B Grutter, A. J., Wong, F. J., Jenkins, C. A., Arenholz, E., Vailionis, A., Suzuki, Y. 2013; 88 (21)

  View details for DOI 10.1103/PhysRevB.88.214410

  View details for Web of Science ID 000328680800001

• Thermopower in quantum confined La-doped SrTiO3 epitaxial heterostructures APPLIED PHYSICS LETTERS Kerman, K., Ramanathan, S., Baniecki, J. D., Ishii, M., Kotaka, Y., Aso, H., Kurihara, K., Schafranek, R., Vailionis, A. 2013; 103 (17)

  View details for DOI 10.1063/1.4826098

  View details for Web of Science ID 000326455100104

• High-Temperature Magnetic Insulating Phase in Ultrathin La0.67Sr0.33MnO3 Films PHYSICAL REVIEW LETTERS Boschker, H., Kautz, J., Houwman, E. P., Siemons, W., Blank, D. H., Huijben, M., Koster, G., Vailionis, A., Rijnders, G. 2012; 109 (15)

  Abstract

  We present a study of the thickness dependence of magnetism and electrical conductivity in ultrathin La0.67Sr0.33MnO3 films grown on SrTiO3 (110) substrates. We found a critical thickness of 10 unit cells below which the conductivity of the films disappeared and simultaneously the Curie temperature increased, indicating a magnetic insulating phase at room temperature. These samples have a Curie temperature of about 560 K with a significant saturation magnetization of 1.2±0.2μ(B)/Mn. The canted antiferromagnetic insulating phase in ultra thin films of n<10 coincides with the occurrence of a higher symmetry structural phase with a different oxygen octahedra rotation pattern. Such a strain engineered phase is an interesting candidate for an insulating tunneling barrier in room temperature spin polarized tunneling devices.

  View details for DOI 10.1103/PhysRevLett.109.157207

  View details for Web of Science ID 000309772600015

  View details for PubMedID 23102365

• Scalable Fabrication of Strongly Textured Organic Semiconductor Micropatterns by Capillary Force Lithography ADVANCED MATERIALS Jo, P. S., Vailionis, A., Park, Y. M., Salleo, A. 2012; 24 (24): 3269-3274

  Abstract

  Strongly textured organic semiconductor micropatterns made of the small molecule dioctylbenzothienobenzothiophene (C(8)-BTBT) are fabricated by using a method based on capillary force lithography (CFL). This technique provides the C(8)-BTBT solution with nucleation sites for directional growth, and can be used as a scalable way to produce high quality crystalline arrays in desired regions of a substrate for OFET applications.

  View details for DOI 10.1002/adma.201200524

  View details for Web of Science ID 000305450500017

  View details for PubMedID 22605625

• Evidence of high-spin Ru and universal magnetic anisotropy in SrRuO3 thin films PHYSICAL REVIEW B Grutter, A. J., Wong, F. J., Arenholz, E., Vailionis, A., Suzuki, Y. 2012; 85 (13)

  View details for DOI 10.1103/PhysRevB.85.134429

  View details for Web of Science ID 000302904900003

• Warm dense matter at the bench-top: Fs-laser-induced confined micro-explosion HIGH ENERGY DENSITY PHYSICS Gamaly, E. G., Vailionis, A., Mizeikis, V., Yang, W., Rode, A. V., Juodkazis, S. 2012; 8 (1): 13-17

  View details for DOI 10.1016/j.hedp.2011.10.003

  View details for Web of Science ID 000300130900003

• Size effects on thermoelectricity in a strongly correlated oxide PHYSICAL REVIEW B Ravichandran, J., Yadav, A. K., Siemons, W., McGuire, M. A., Wu, V., Vailionis, A., Majumdar, A., Ramesh, R. 2012; 85 (8)

  View details for DOI 10.1103/PhysRevB.85.085112

  View details for Web of Science ID 000300566600003

• Synthesis of super-dense phase of aluminum under extreme pressure and temperature conditions created by femtosecond laser pulses in sapphire ADVANCED FABRICATION TECHNOLOGIES FOR MICRO/NANO OPTICS AND PHOTONICS V Mizeikis, V., Vailionis, A., Gamaly, E. G., Yang, W., Rode, A., Juodkazis, S. 2012; 8249

  View details for DOI 10.1117/12.906946

  View details for Web of Science ID 000302640700003

• Electronic transport behavior of off-stoichiometric La and Nb doped SrxTiyO3-delta epitaxial thin films and donor doped single-crystalline SrTiO3 APPLIED PHYSICS LETTERS Baniecki, J. D., Ishii, M., Aso, H., Kobayashi, K., Kurihara, K., Yamanaka, K., Vailionis, A., Schafranek, R. 2011; 99 (23)

  View details for DOI 10.1063/1.3664397

  View details for Web of Science ID 000298006100039

• Uniaxial contribution to the magnetic anisotropy of La0.67Sr0.33MnO3 thin films induced by orthorhombic crystal structure JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS Boschker, H., Mathews, M., Brinks, P., Houwman, E., Vailionis, A., Koster, G., Blank, D. H., Rijnders, G. 2011; 323 (21): 2632-2638

  View details for DOI 10.1016/j.jmmm.2011.05.051

  View details for Web of Science ID 000292770700016

• Synthesis of high-pressure phases of silica by laser-induced optical breakdown APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING Mizeikis, V., Kohara, S., Onishi, Y., Hirao, N., Saito, A., Vailionis, A., Juodkazis, S. 2011; 104 (3): 903-906

  View details for DOI 10.1007/s00339-011-6437-6

  View details for Web of Science ID 000293963200024

• Evidence of superdense aluminium synthesized by ultrafast microexplosion NATURE COMMUNICATIONS Vailionis, A., Gamaly, E. G., Mizeikis, V., Yang, W., Rode, A. V., Juodkazis, S. 2011; 2

  Abstract

  At extreme pressures and temperatures, such as those inside planets and stars, common materials form new dense phases with compacted atomic arrangements and unusual physical properties. The synthesis and study of new phases of matter at pressures above 100 GPa and temperatures above 10(4) K--warm dense matter--may reveal the functional details of planet and star interiors, and may lead to materials with extraordinary properties. Many phases have been predicted theoretically that may be realized once appropriate formation conditions are found. Here we report the synthesis of a superdense stable phase of body-centred-cubic aluminium, predicted by first-principles theories to exist at pressures above 380 GPa. The superdense Al phase was synthesized in the non-equilibrium conditions of an ultrafast laser-induced microexplosion confined inside sapphire (α-Al(2)O(3)). Confined microexplosions offer a strategy to create and recover high-density polymorphs, and a simple method for tabletop study of warm dense matter.

  View details for DOI 10.1038/ncomms1449

  View details for Web of Science ID 000294806500038

  View details for PubMedID 21863012

  View details for PubMedCentralID PMC3265372

• Optimized fabrication of high-quality La0.67Sr0.33MnO3 thin films considering all essential characteristics JOURNAL OF PHYSICS D-APPLIED PHYSICS Boschker, H., Huijben, M., Vailionis, A., Verbeeck, J., Van Aert, S., Luysberg, M., Bals, S., Van Tendeloo, G., Houwman, E. P., Koster, G., Blank, D. H., Rijnders, G. 2011; 44 (20)

  View details for DOI 10.1088/0022-3727/44/20/205001

  View details for Web of Science ID 000290150900001

• Structural Characterization of Femtosecond Laser Modified Regions Inside Sapphire JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY Juodkazis, S., Kohara, S., Ohishi, Y., Hirao, N., Vailionis, A., Mizeikis, V., Saito, A., Rode, A. 2011; 11 (4): 2931-2936

  Abstract

  We report on structural characterization of sapphire photomodified by voids of sub-wavelength diameter surrounded by amorphised regions formed after exposure by tightly-focused femtosecond laser pulses of 800 nm wavelength and 150 fs duration at the single and double-pulse irradiation inside crystalline sapphire. Regrowth of a crystalline phase near the edge between the amorphous and crystalline phases was observed by transmission electron microscopy (TEM) in the case of double-pulse-irradiated locations. Regions patterned by single-pulse-induced voids inside sapphire were characterized by synchrotron X-ray diffraction (XRD) technique. The XRD patterns indicate presence of an expanded phase of the host crystal. The origin of structural changes observed in TEM and XRD is discussed and is consistent with fast thermal quenching.

  View details for DOI 10.1166/jnn.2011.3919

  View details for Web of Science ID 000289176100027

  View details for PubMedID 21776656

• Controlling Electric Dipoles in Nanodielectrics and Its Applications for Enabling Air-Stable n-Channel Organic Transistors NANO LETTERS Chung, Y., Verploegen, E., Vailionis, A., Sun, Y., Nishi, Y., Murmann, B., Bao, Z. 2011; 11 (3): 1161-1165

  Abstract

  We present a new method to manipulate the channel charge density of field-effect transistors using dipole-generating self-assembled monolayers (SAMs) with different anchor groups. Our approach maintains an ideal interface between the dipole layers and the semiconductor while changing the built-in electric potential by 0.41-0.50 V. This potential difference can be used to change effectively the electrical properties of nanoelectronic devices. We further demonstrate the application of the SAM dipoles to enable air-stable operation of n-channel organic transistors.

  View details for DOI 10.1021/nl104087u

  View details for Web of Science ID 000288061500043

  View details for PubMedID 21323381

• Misfit strain accommodation in epitaxial ABO(3) perovskites: Lattice rotations and lattice modulations PHYSICAL REVIEW B Vailionis, A., Boschker, H., Siemons, W., Houwman, E. P., Blank, D. H., Rijnders, G., Koster, G. 2011; 83 (6)

  View details for DOI 10.1103/PhysRevB.83.064101

  View details for Web of Science ID 000287364700004

• Synthesis of Materials by Ultrafast Microexplosion Conference on Lasers and Electro-Optics (CLEO) Vailionis, A., Gamaly, E. G., Mizeikis, V., Yang, W., Rode, A., Juodkazis, S. IEEE. 2011

  View details for Web of Science ID 000295612402204

• Structural changes in femtosecond laser modified regions inside fused silica JOURNAL OF OPTICS Juodkazis, S., Kohara, S., Ohishi, Y., Hirao, N., Vailionis, A., Mizeikis, V., Saito, A., Rode, A. 2010; 12 (12)

  View details for DOI 10.1088/2040-8978/12/12/124007

  View details for Web of Science ID 000285160900008

• 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

• Enhanced magnetism in epitaxial SrRuO3 thin films APPLIED PHYSICS LETTERS Grutter, A., Wong, F., Arenholz, E., Liberati, M., Vailionis, A., Suzuki, Y. 2010; 96 (8)

  View details for DOI 10.1063/1.3327512

  View details for Web of Science ID 000275027200058

• Anisotropic stress relief mechanism in epitaxial La0.67Sr0.33MnO3 films APPLIED PHYSICS LETTERS Vailionis, A., Boschker, H., Houwman, E., Koster, G., Rijnders, G., Blank, D. H. 2009; 95 (15)

  View details for DOI 10.1063/1.3249583

  View details for Web of Science ID 000270915700053

• Strong uniaxial in-plane magnetic anisotropy of (001)- and (011)-oriented La0.67Sr0.33MnO3 thin films on NdGaO3 substrates PHYSICAL REVIEW B Boschker, H., Mathews, M., Houwman, E. P., Nishikawa, H., Vailionis, A., Koster, G., Rijnders, G., Blank, D. H. 2009; 79 (21)

  View details for DOI 10.1103/PhysRevB.79.214425

  View details for Web of Science ID 000267699200086

• Room temperature epitaxial stabilization of a tetragonal phase in ARuO(3) (A=Ca and Sr) thin films APPLIED PHYSICS LETTERS Vailionis, A., Siemons, W., Koster, G. 2008; 93 (5)

  View details for DOI 10.1063/1.2967878

  View details for Web of Science ID 000258335900032

• Strain-induced single-domain growth of epitaxial SrRuO3 layers on SrTiO3: A high-temperature x-ray diffraction study APPLIED PHYSICS LETTERS Vailionis, A., Siemons, W., Koster, G. 2007; 91 (7)

  View details for DOI 10.1063/1.2771087

  View details for Web of Science ID 000248866600034

• Dependence of the electronic structure of SrRuO3 and its degree of correlation on cation off-stoichiometry PHYSICAL REVIEW B Siemons, W., Koster, G., Vailionis, A., Yamamoto, H., Blank, D. H., Beasley, M. R. 2007; 76 (7)

  View details for DOI 10.1103/PhysRevB.76.075126

  View details for Web of Science ID 000249155300063

• AFM and complementary XRD measurements of in situ grown YBCO films obtained by pulsed laser deposition Symposium on Photon-Assisted Synthesis and Processing of Functional Materials held at the 2006 EMRS Spring Meeting Branescu, M., Vailionis, A., Huh, J., Moldovan, A., Socol, G. ELSEVIER SCIENCE BV. 2007: 8179–83

  View details for DOI 10.1016/j.apsusc.2007.02.160

  View details for Web of Science ID 000249020500107

• Spectroscopic and X-ray diffraction study of high T-c epitaxial YBCO thin films obtained by pulsed laser deposition Symposium on Current Trends in Optical and X-Ray Meterology of Advanced Materials for Nanoscale Devices held at the 2005 MRS Spring Meeting Branescu, M., Vailionis, A., Gartner, M., Anastasescu, M. ELSEVIER SCIENCE BV. 2006: 400–404

  View details for DOI 10.1016/j.apsusc.2006.06.022

  View details for Web of Science ID 000242317500077

• Ion beam and complementary SEM and XRD characterization of YBa2Cu3O7-x films obtained by pulsed laser deposition 17th International Conference on Ion Beam Analysis Branescu, M., Thome, L., Pantelica, D., Ward, I., Vailionis, A., Ionescu, P. ELSEVIER SCIENCE BV. 2006: 911–914

  View details for DOI 10.1016/j.nimb.2006.03.162

  View details for Web of Science ID 000239545000220

• In situ grown epitaxial YBa2Cu3O7-x thin films by pulsed laser deposition under reduced oxygen pressure during cool-down time Symposium on Advances in Laser and Lamp Processing of Functional Materials Branescu, M., Vailionis, A., Ward, I., Huh, J., Socol, G. ELSEVIER SCIENCE BV. 2006: 4573–77

  View details for DOI 10.1016/j.apsusc.2005.07.137

  View details for Web of Science ID 000238623200046

• Thickness-dependent properties of (110)-oriented La1.2Sr1.8Mn2O7 thin films JOURNAL OF APPLIED PHYSICS Takamura, Y., Chopdekar, R. V., Grepstad, J. K., Suzuki, Y., Marshall, A. F., Vailionis, A., Zheng, H., Mitchell, J. F. 2006; 99 (8)

  View details for DOI 10.1063/1.2162087

  View details for Web of Science ID 000237404200790

• Polarized XANES and EXAFS spectroscopic investigation into copper(II) complexes on vermiculite GEOCHIMICA ET COSMOCHIMICA ACTA Furnare, L. J., Vailionis, A., Strawn, D. G. 2005; 69 (22): 5219-5231

  View details for DOI 10.1016/j.gca.2005.06.020

  View details for Web of Science ID 000234417400004

• Molecular-level investigation into copper complexes on vermiculite: Effect of reduction of structural iron on copper complexation JOURNAL OF COLLOID AND INTERFACE SCIENCE Furnare, L. J., Vailionis, A., Strawn, D. G. 2005; 289 (1): 1-13

  Abstract

  In this paper we present results that describe the speciation of Cu sorbed to the clay mineral vermiculite, with special attention to the effects of reduction on Cu sorption complexes. Sorption complexes were studied using powdered extended X-ray absorption fine structure (EXAFS) spectroscopy, polarized EXAFS spectroscopy, and X-ray diffraction (XRD). Ionic strength (I), background ion, and clay reduction (structural iron) were varied in the sorption samples. At low I EXAFS results indicate that Cu was surrounded by up to six water molecules sorbed in the interlayer of reduced vermiculite. EXAFS results from Cu-equilibrated reduced vermiculite with high I Ca background electrolyte revealed that Cu was surrounded by 4 O atoms at 1.95 Angatroms and 8 second shell O atoms at 3.14 Angstroms. Angular dependence of the second shell O atoms interpreted from the polarized-EXAFS spectra indicated that the atoms are out of plane from the basal plane of the vermiculite (inclined approximately 25 degrees from the ab plane). The local atomic environment and angular dependence of the EXAFS spectra suggest that the Cu atoms are adsorbed above the hexagonal cavities of the reduced clay mineral and form a Cu dimer in the interlayer. This adsorption mechanism was not observed in the non-reduced vermiculite under identical equilibration conditions. Our results provide molecular level evidence that Cu sorption mechanisms on vermiculite are dependent on solution conditions, such as redox potential and background electrolyte. These results can be used to develop better models of Cu sorption mechanisms on clay mineral surfaces.

  View details for DOI 10.1016/j.jcis.2005.03.068

  View details for Web of Science ID 000230184200001

  View details for PubMedID 16009212

• Determination of absolute orientation-dependent TiN(001) and TiN(111) step energies VACUUM Kodambaka, S., Khare, S. V., Petrova, V., Vailionis, A., Petrov, I., Greene, J. E. 2004; 74 (3-4): 345-351

  View details for DOI 10.1016/j.vacuum.2004.01.015

  View details for Web of Science ID 000221843100001

• A multichannel superconducting tunnel junction detector for high-resolution X-ray spectroscopy of magnesium diboride films Applied Superconductivity Conference Friedrich, S., Vailionis, A., Drury, O., Niedermayr, T., Funk, T., Kang, W. N., Choi, E. M., Kim, H. J., Lee, S. I., Cramer, S. P., Kim, C., Labov, S. E. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. 2003: 1114–19

  View details for DOI 10.1109/TASC.2003.814169

  View details for Web of Science ID 000184241700259

• In situ high-temperature scanning tunneling microscopy studies of two-dimensional TiN island coarsening kinetics on TiN(001) SURFACE SCIENCE Kodambaka, S., Petrova, V., Vailionis, A., Petrov, I., Greene, J. E. 2003; 526 (1-2): 85-96

  View details for Web of Science ID 000181211300014

• Absolute orientation-dependent TiN(001) step energies from two-dimensional equilibrium island shape and coarsening measurements on epitaxial TiN(001) layers (vol 513, pg 468, 2002) SURFACE SCIENCE Kodambaka, S., Khare, S. V., Petrova, V., Vailionis, A., Petrov, I., Greene, J. E. 2003; 523 (3): 316-316

  View details for Web of Science ID 000180614600014

• Dopant deactivation in heavily Sb doped Si (001): A high-resolution x-ray diffraction and transmission electron microscopy study JOURNAL OF APPLIED PHYSICS Takamura, Y., Vailionis, A., Marshall, A. F., Griffin, P. B., Plummer, J. D. 2002; 92 (9): 5503-5507

  View details for DOI 10.1063/1.1510953

  View details for Web of Science ID 000178767200099

• Absolute orientation-dependent TiN(001) step energies from two-dimensional equilibrium island shape and coarsening measurements on epitaxial TiN(001) layers SURFACE SCIENCE Kodambaka, S., Khare, S. V., Petrova, V., Vailionis, A., Petrov, I., Greene, J. E. 2002; 513 (3): 468-474

  View details for Web of Science ID 000177319500011

• Hydrogen-mediated quenching of strain-induced surface roughening during gas-source molecular beam epitaxy of fully-coherent Si0.7Ge0.3 layers on Si(001) JOURNAL OF APPLIED PHYSICS Spila, T., Desjardins, P., Vailionis, A., Kim, H., Taylor, N., Cahill, D. G., Greene, J. E., Guillon, S., Masut, R. A. 2002; 91 (6): 3579-3588

  View details for DOI 10.1063/1.1448680

  View details for Web of Science ID 000174182500014

• TiN(001) and TiN(111) island coarsening kinetics: in-situ scanning tunneling microscopy studies THIN SOLID FILMS Kodambaka, S., Petrova, V., Vailionis, A., Desjardins, P., Cahill, D. G., Petrov, I., Greene, J. E. 2001; 392 (2): 164-168

  View details for Web of Science ID 000169954900005

• Misfit strain induced lattice distortions in heteroepitaxially grown LaxCa1-xMnO3 thin films studied by extended x-ray absorption fine structure and high-resolution x-ray diffraction JOURNAL OF APPLIED PHYSICS Miniotas, A., Vailionis, A., Svedberg, E. B., Karlsson, U. O. 2001; 89 (4): 2134-2137

  View details for Web of Science ID 000166688300021

• Pathway for the strain-driven two-dimensional to three-dimensional transition during growth of Ge on Si(001) PHYSICAL REVIEW LETTERS Vailionis, A., Cho, B., Glass, G., Desjardins, P., Cahill, D. G., Greene, J. E. 2000; 85 (17): 3672-3675

  View details for Web of Science ID 000089996600032

• In-situ high-temperature scanning-tunnelling-microscopy studies of two-dimensional island-decay kinetics on atomically smooth TiN(001) SURFACE REVIEW AND LETTERS Kodambaka, S., Petrova, V., Vailionis, A., Desjardins, P., Cahill, D. G., Petrov, I., Greene, J. E. 2000; 7 (5-6): 589-593

  View details for Web of Science ID 000166893600014

• Ge(011)-c(8x10) surface structure and hydrogen desorption pathways: a temperature-programmed desorption and scanning tunneling microscopy study SURFACE SCIENCE Kim, H., Vailionis, A., Cahill, D. G., Greene, J. E. 2000; 457 (3): 337-344

  View details for Web of Science ID 000087927000009

• Growth and physical properties of epitaxial metastable cubic TaN(001) APPLIED PHYSICS LETTERS Shin, C. S., Gall, D., Desjardins, P., Vailionis, A., Kim, H., Petrov, I., Greene, J. E., Oden, M. 1999; 75 (24): 3808-3810

  View details for Web of Science ID 000084242600024

• Cation disorder in superconducting HgBa2CaCu2O6+delta films prepared on SrTiO3 substrates PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS Vailionis, A., Brazdeikis, A., Bryntse, I., Flodstrom, A. S. 1999; 328 (1-2): 67-70

  View details for Web of Science ID 000084377400009

• Electrically active and inactive B lattice sites in ultrahighly B doped Si(001): An x-ray near-edge absorption fine-structure and high-resolution diffraction study PHYSICAL REVIEW LETTERS Vailionis, A., Glass, G., Desjardins, P., Cahill, D. G., Greene, J. E. 1999; 82 (22): 4464-4467

  View details for Web of Science ID 000080546900024

• Observation of local oxygen displacements in CuO2 planes induced by a misfit strain in heteroepitaxially grown infinite-layer-structure Ca1-xSrxCuO2 films PHYSICAL REVIEW B Vailionis, A., Brazdeikis, A., Flodstrom, A. S. 1997; 55 (10): R6152-R6155

  View details for Web of Science ID A1997WP34500015

• Microstructural properties of Bi2Sr2Can-1CunOy multilayers grown by molecular beam epitaxy PHYSICAL REVIEW B Vailionis, A., Brazdeikis, A., Flodstrom, A. S. 1996; 54 (21): 15457-15462

  View details for Web of Science ID A1996VY20100092

• MOLECULAR-BEAM EPITAXY GROWTH AND MICROSTRUCTURE OF THIN SUPERCONDUCTING BI2SR2CACU2OX FILMS PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS Brazdeikis, A., Vailionis, A., Flodstrom, A. S., Traeholt, C. 1995; 253 (3-4): 383-390

  View details for Web of Science ID A1995TE08400023

• GROWTH-KINETICS-INDUCED STRUCTURAL DISORDER IN BI-2(SR1-XCAX)(3)CU2OY THIN-FILMS STUDIED BY X-RAY-DIFFRACTION PHYSICAL REVIEW B Vailionis, A., Brazdeikis, A., Flodstrom, A. S. 1995; 51 (5): 3097-3103

  View details for Web of Science ID A1995QG31200060

• Superconducting multilayers: Microstructural properties studied by x-ray diffraction Symposium on Structure and Properties of Multilayered Thin Films, at the 1995 MRS Spring Meeting Vailionis, A., Brazdeikis, A., Flodstrom, A. S. MATERIALS RESEARCH SOC. 1995: 217–222

  View details for Web of Science ID A1995BE43P00035

• LAYER-BY-LAYER GROWTH OF BI2SR2CAN-1CUNOX FILMS WITH N-GREATER-THAN-OR-EQUAL-TO-3 BY MOLECULAR-BEAM EPITAXY PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS Brazdeikis, A., Vailionis, A., Flodstrom, A. S. 1994; 235: 711-712

  View details for Web of Science ID A1994QA39000285

• HYDROGEN-INDUCED OXYGEN NONSTOICHIOMETRY OF Y2BACUO5 FIZIKA TVERDOGO TELA Jukna, A., Vengalis, B., SHIKTOROVAS, N., Lisauskas, V., Vailionis, A., Jasutis, V. 1993; 35 (5): 1160-1166

  View details for Web of Science ID A1993LN59500005

• ULTRAFAST ELECTRICAL SUPERCONDUCTING TO NORMAL STATES SWITCHING IN Y-BA-CU-O AND BI-SR-CA-CU-O MICROSTRIPS SYMP ON LAYERED SUPERCONDUCTORS : FABRICATION, PROPERTIES, AND APPLICATIONS Balevicius, S., BICIUNAS, A., Butkute, R., Jasutis, V., Lisauskas, V., Vailionis, A., Flodstrom, A., Vengalis, B. MATERIALS RESEARCH SOC. 1992: 589–593

  View details for Web of Science ID A1992BX05X00090