Quasi-One-Dimensional Higher-Order Topological Insulators

ORAL

Abstract

Quasi-1D β-Bi4X4 (X=Br, I) are prototype weak topological insulators (TI). For the α phases, recent high-throughput database screening suggests that Bi4Br4 is a rare higher-order TI (HOTI) whereas Bi4I4 has trivial symmetry indicators. We show that in fact the two α phases are both pristine HOTIs yet with distinct hinge state patterns. The location of inversion center dictates Bi4Br4 (Bi4I4) to feature opposite (the same) dimerizations of a surface or intrinsic (bulk or extrinsic) origin at two side surfaces. Our results imply the possible existence of many topological materials beyond the scope of symmetry indicators and establish a new TI paradigm in a unique material platform. [arXiv:2005.14710]

*This work was supported by National Science Foundation under Grant Nos. DMR-1921581 through the DMREF program and DMR-1945351 through the CAREER program, Army Research Office under Grant No. W911NF-18-1-0416, UTD research enhancement fund, National Research Foundation of Korea under Grant Nos. 2016H1A2A1907780 through the Global PhD Fellowship Program and 2018R1A2B6007837, SNU Creative Pioneering Researchers Program, and National Natural Science Foundation of China under Grants Nos. 11922401 and 11774028.

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Presenters

  • Chiho Yoon

    • University of Texas at Dallas and Seoul National University

Authors

  • Chiho Yoon

    • University of Texas at Dallas and Seoul National University

  • Cheng-Cheng Liu

    • Beijing Institute of Technology

  • Hongki Min

    • Seoul National University

  • Fan Zhang

    • University of Texas at Dallas
    • Department of Physics, The University of Texas at Dallas
    • University of Texas, Dallas
    • Department of Physics, University of Texas at Dallas