Bio


Education: Ph.D, Physics, Tsinghua University, Beijing, China, 2015
B.A, Physics, Lanzhou University, Lanzhou, China, 2009

Professional Education


  • Doctor of Philosophy, Tsinghua University (2015)

Stanford Advisors


Lab Affiliations


All Publications


  • Topological Superconductivity on the Surface of Fe-Based Superconductors PHYSICAL REVIEW LETTERS Xu, G., Lian, B., Tang, P., Qi, X., Zhang, S. 2016; 117 (4)

    Abstract

    As one of the simplest systems for realizing Majorana fermions, the topological superconductor plays an important role in both condensed matter physics and quantum computations. Based on ab initio calculations and the analysis of an effective 8-band model with superconducting pairing, we demonstrate that the three-dimensional extended s-wave Fe-based superconductors such as Fe_{1+y}Se_{0.5}Te_{0.5} have a metallic topologically nontrivial band structure, and exhibit a normal-topological-normal superconductivity phase transition on the (001) surface by tuning the bulk carrier doping level. In the topological superconductivity (TSC) phase, a Majorana zero mode is trapped at the end of a magnetic vortex line. We further show that the surface TSC phase only exists up to a certain bulk pairing gap, and there is a normal-topological phase transition driven by the temperature, which has not been discussed before. These results pave an effective way to realize the TSC and Majorana fermions in a large class of superconductors.

    View details for DOI 10.1103/PhysRevLett.117.047001

    View details for Web of Science ID 000380121400005

    View details for PubMedID 27494494

  • Stable Dirac semimetal in the allotropes of group-IV elements PHYSICAL REVIEW B Cao, W., Tang, P., Zhang, S., Duan, W., Rubio, A. 2016; 93 (24)
  • Manipulation of Magnetic Properties by Oxygen Vacancies in Multiferroic YMnO3 ADVANCED FUNCTIONAL MATERIALS Cheng, S., Li, M., Deng, S., Bao, S., Tang, P., Duan, W., Ma, J., Nan, C., Zhu, J. 2016; 26 (21): 3589-3598
  • Large-gap quantum spin Hall states in decorated stanene grown on a substrate PHYSICAL REVIEW B Xu, Y., Tang, P., Zhang, S. 2015; 92 (8)
  • Robust Gapless Surface State and Rashba-Splitting Bands upon Surface Deposition of Magnetic Cr on Bi2Se3. Nano letters Wang, E., Tang, P., Wan, G., Fedorov, A. V., Miotkowski, I., Chen, Y. P., Duan, W., Zhou, S. 2015; 15 (3): 2031-2036

    Abstract

    The interaction between magnetic impurities and the gapless surface state is of critical importance for realizing novel quantum phenomena and new functionalities in topological insulators. By combining angle-resolved photoemission spectroscopic experiments with density functional theory calculations, we show that surface deposition of Cr atoms on Bi2Se3 does not lead to gap opening of the surface state at the Dirac point, indicating the absence of long-range out-of-plane ferromagnetism down to our measurement temperature of 15 K. This is in sharp contrast to bulk Cr doping, and the origin is attributed to different Cr occupation sites. These results highlight the importance of nanoscale configuration of doped magnetic impurities in determining the electronic and magnetic properties of topological insulators.

    View details for DOI 10.1021/nl504900s

    View details for PubMedID 25710329

  • Stable two-dimensional dumbbell stanene: A quantum spin Hall insulator PHYSICAL REVIEW B Tang, P., Chen, P., Cao, W., Huang, H., Cahangirov, S., Xian, L., Xu, Y., Zhang, S., Duan, W., Rubio, A. 2014; 90 (12)
  • Chemical-Potential-Dependent Gap Opening at the Dirac Surface States of Bi2Se3 Induced by Aggregated Substitutional Cr Atoms (vol 112, 056801, 2014) PHYSICAL REVIEW LETTERS Chang, C., Tang, P., Wang, Y., Feng, X., Li, K., Zhang, Z., Wang, Y., Wang, L., Chen, X., Liu, C., Duan, W., He, K., Ma, X., Xue, Q. 2014; 112 (10)
  • Sulfur immobilization and lithium storage on defective graphene: A first-principles study APPLIED PHYSICS LETTERS Zhao, W., Chen, P., Tang, P., Li, Y., Wu, J., Duan, W. 2014; 104 (4)

    View details for DOI 10.1063/1.4862983

    View details for Web of Science ID 000331209900096

  • Weak topological insulators induced by the interlayer coupling: A first-principles study of stacked Bi2TeI PHYSICAL REVIEW B Tang, P., Yan, B., Cao, W., Wu, S., Felser, C., Duan, W. 2014; 89 (4)
  • Large-Gap Quantum Spin Hall Insulators in Tin Films PHYSICAL REVIEW LETTERS Xu, Y., Yan, B., Zhang, H., Wang, J., Xu, G., Tang, P., Duan, W., Zhang, S. 2013; 111 (13)

    Abstract

    The search for large-gap quantum spin Hall (QSH) insulators and effective approaches to tune QSH states is important for both fundamental and practical interests. Based on first-principles calculations we find two-dimensional tin films are QSH insulators with sizable bulk gaps of 0.3 eV, sufficiently large for practical applications at room temperature. These QSH states can be effectively tuned by chemical functionalization and by external strain. The mechanism for the QSH effect in this system is band inversion at the Γ point, similar to the case of a HgTe quantum well. With surface doping of magnetic elements, the quantum anomalous Hall effect could also be realized.

    View details for DOI 10.1103/PhysRevLett.111.136804

    View details for Web of Science ID 000324762300018

    View details for PubMedID 24116803

  • Field-Effect Birefringent Spin Lens in Ultrathin Film of Magnetically Doped Topological Insulators PHYSICAL REVIEW LETTERS Zhao, L., Tang, P., Gu, B., Duan, W. 2013; 111 (11)

    Abstract

    We investigate the low-energy electron dynamics in two-dimensional ultrathin film of magnetically doped topological insulators in the context of gate-tuned coherent spin manipulation. Our first-principles calculations for such film unambiguously identify its spin-resolved topological band structure arising from spin-orbit coupling and time-reversal symmetry breaking. Exploiting this characteristic, we predict a negative birefraction for chiral electron tunneling through a gate-controlled p-n interface in the film, analogous to optical birefringence. By fine-tuning the gate voltage, a series of unusual phenomena, including electron double focusing, spatial modulation of spin polarizations, and quantum-interference-induced beating patterns, could be efficiently implemented, offering a powerful platform to establish spin-resolved electron optics by all-electrical means.

    View details for DOI 10.1103/PhysRevLett.111.116601

    View details for Web of Science ID 000324233400016

    View details for PubMedID 24074112

  • Electronic structure of silicene on Ag(111): Strong hybridization effects PHYSICAL REVIEW B Cahangirov, S., Audiffred, M., Tang, P., Iacomino, A., Duan, W., Merino, G., Rubio, A. 2013; 88 (3)
  • Topological insulators in transition-metal intercalated graphene: The role of d electrons in significantly increasing the spin-orbit gap PHYSICAL REVIEW B Li, Y., Tang, P., Chen, P., Wu, J., Gu, B., Fang, Y., Zhang, S. B., Duan, W. 2013; 87 (24)
  • Topology-Driven Magnetic Quantum Phase Transition in Topological Insulators SCIENCE Zhang, J., Chang, C., Tang, P., Zhang, Z., Feng, X., Li, K., Wang, L., Chen, X., Liu, C., Duan, W., He, K., Xue, Q., Ma, X., Wang, Y. 2013; 339 (6127): 1582-1586

    Abstract

    The breaking of time reversal symmetry in topological insulators may create previously unknown quantum effects. We observed a magnetic quantum phase transition in Cr-doped Bi2(SexTe1-x)3 topological insulator films grown by means of molecular beam epitaxy. Across the critical point, a topological quantum phase transition is revealed through both angle-resolved photoemission measurements and density functional theory calculations. We present strong evidence that the bulk band topology is the fundamental driving force for the magnetic quantum phase transition. The tunable topological and magnetic properties in this system are well suited for realizing the exotic topological quantum phenomena in magnetic topological insulators.

    View details for DOI 10.1126/science.1230905

    View details for Web of Science ID 000316731600042

    View details for PubMedID 23539598

  • Metallicity retained by covalent functionalization of graphene with phenyl groups NANOSCALE Tang, P., Chen, P., Wu, J., Kang, F., Li, J., Rubio, A., Duan, W. 2013; 5 (16): 7537-7543

    Abstract

    To resolve the controversy over the functionalization effect on conductivity, we systematically investigate the structural and electronic properties of graphene covalently functionalized with phenyl groups. Using first-principles calculations combined with the model Hamiltonian analysis, we find that the structural stability, electronic and transport properties of the functionalized graphene are strongly dependent on the adsorption site of the phenyl groups. In detail, double-side functionalized graphene is energetically more favorable than single-side functionalized graphene, and more importantly, they exhibit an exotic non-magnetic metallic state and a magnetic semiconducting state, respectively. For covalently double-side functionalized graphene, two bands contributed by π electrons of graphene cross at the Fermi level with the preserved electron-hole symmetry, and the Fermi velocity of carriers could be flexibly tuned by changing the coverage of the phenyl groups. These results provide an insight into the experimental observation [ACS Nano 2011, 5, 7945], interpreting the origin of the increase in the conductivity of graphene covalently functionalized with phenyl groups. Our work reveals the great potential of these materials in future nanoelectronics or sensors by controlling the attachment of phenyl groups.

    View details for DOI 10.1039/c3nr01572f

    View details for Web of Science ID 000322315600056

    View details for PubMedID 23836075

  • Design of strain-engineered quantum tunneling devices for topological surface states APPLIED PHYSICS LETTERS Zhao, L., Liu, J., Tang, P., Duan, W. 2012; 100 (13)

    View details for DOI 10.1063/1.3699023

    View details for Web of Science ID 000302230800018

  • Electronic and magnetic properties of boron nitride nanoribbons with topological line defects RSC ADVANCES Tang, P., Zou, X., Wang, S., Wu, J., Liu, H., Duan, W. 2012; 2 (15): 6192-6199

    View details for DOI 10.1039/c2ra20306e

    View details for Web of Science ID 000306216600014