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Topological Surface States in an Ideal Weak Topological Insulator

ORAL

Abstract

The quasi-one-dimensional bismuth halides Bi4X4 (X = I, Br) constitute a recently realized material platform that harbors a number of non-trivial topological phases such as weak topological insulator (TI) and higher-order TI. In addition, superconductivity has been observed under pressure, suggesting potentially important roles played by electronic/structural instabilities. Thus, Bi4X4 is a promising platform that facilitates non-trivial topology in the presence of electronic/structural instabilities. Therefore, characterizing these compounds’ topological phases as well as finding the origin of the instabilities become essential for both a deeper understanding and future topological engineering. Among the Bi4X4 series of materials, we find a specific case of the simplest AA stacking order of the crystal structure at cryogenic temperatures, enabling us to conduct high energy resolution angle-resolved photoemission spectroscopy (ARPES) experiments. In this talk, I will present our ARPES results for identification of its topological character as a weak TI by measurements on both (100) and (001) cleaved surfaces. Furthermore, combined with an effective Hamiltonian, characterization for in-gap van Hove singularities purely derived from topologically non-trivial surface states will be presented.

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Presenters

  • Ji Seop Oh

    Rice University, University of California Berkeley, University of California Berkeley

Authors

  • Ji Seop Oh

    Rice University, University of California Berkeley, University of California Berkeley

  • Tianyi Xu

    University of Texas at Dallas

  • Nikhil Dhale

    University of Texas at Dallas

  • Sheng Li

    University of Texas at Dallas

  • Chao Lei

    University of Texas at Austin

  • Hanlin Wu

    University of Texas at Dallas, The University of Texas at Dallas

  • Jianwei Huang

    Rice University

  • Makoto Hashimoto

    SLAC National Accelerator Laboratory, SLAC - Natl Accelerator Lab, SLAC National Accelerator Lab

  • Donghui Lu

    SLAC - Natl Accelerator Lab, SLAC National Accelerator Laboratory, SLAC National Accelerator Lab

  • Christopher Jozwiak

    Lawrence Berkeley National Laboratory, Lawrence Berkeley National Lab, E. O. Lawrence Berkeley National Laboratory, lawrence berkeley lab, Advanced Light Source, Lawrence Berkeley National Laboratory

  • Aaron Bostwick

    Lawrence Berkeley National Laboratory, Lawrence Berkeley National Lab, E. O. Lawrence Berkeley National Laboratory, lawrence berkeley lab, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley

  • Eli Rotenberg

    Lawrence Berkeley National Laboratory

  • Bing Lv

    University of Texas at Dallas

  • Fan Zhang

    UT Dallas, University of Texas at Dallas

  • Robert J Birgeneau

    University of California, Berkeley

  • Ming Yi

    Rice University, Rice Univ