Topological hinge state in a 1D stacking material

ORAL

Abstract

Due to a higher order bulk boundary correspondence, a higher-order topological insulator hosts one-dimensional helical edge states around the hinges of the crystal. However, spectroscopic evidence for topological hinge states has been so far limited to semimetallic materials [1], where the measured edge conductivity is blurred by bulk carries. In this contribution, we show evidence for topological hinge states in a semiconducting quasi-one-dimensional material. Importantly, the crystal has naturally cleavable top and side surfaces which are stacked via van-der-Waals forces, and therefore the electronic structure around the hinge can be investigated in a cleaved surface or in an exfoliated thin flake. Our experiments by high-resolution angle-resolved photoemission spectroscopy reveal quasi-1D states inside the bulk band gap. Moreover, the corresponding signals with high conductivity are detected at the edges of the crystal by microwave impedance microscopy. These observations, therefore, indicate the existence of topological hinge states in a 1D stacking material.
[1] F. Schindler et al., Nat. Phys. 14, 918 (2018).

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Presenters

  • Ryo Noguchi

    • University of Tokyo

Authors

  • Ryo Noguchi

    • University of Tokyo

  • Masaru Kobayashi

    • Tokyo Institute of Technology

  • Kenta Kuroda

    • Univ of Tokyo
    • University of Tokyo
    • Institute for Solid State Physics, University of Tokyo

  • Takanari Takahashi

    • Tokyo Institute of Technology

  • Zhanzhi Jiang

    • University of Texas at Austin

  • Zifan Xu

    • University of Texas at Austin

  • Daehun Lee

    • University of Texas at Austin

  • Motoaki Hirayama

    • RIKEN
    • RIKEN Center for Emergent Matter Science

  • Masayuki Ochi

    • Physics, Osaka University
    • Department of Physics, Osaka University
    • Osaka Univ
    • Osaka University

  • Tetsuro Shirasawa

    • National Institute of Advanced Industrial Science and Technology

  • Peng Zhang

    • University of Tokyo

  • Chun Lin

    • University of Tokyo

  • Cédric Bareille

    • University of Tokyo

  • Koichiro Yaji

    • University of Tokyo
    • Institute for Solid State Physics, University of Tokyo
    • Institute for Solid State Physics, The University of Tokyo

  • Ayumi Harasawa

    • University of Tokyo
    • Institute for Solid State Physics, University of Tokyo

  • Viktor Kandyba

    • Elettra - Sincrotrone Trieste
    • Elettra - Sincrotrone Trieste S.C.p.A

  • Alessio Giampietri

    • Elettra - Sincrotrone Trieste

  • Alex Victorovich Barinov

    • Elettra - Sincrotrone Trieste
    • Elettra - Sincrotrone Trieste S.C.p.A

  • Timur Kim

    • Diamond Light Source

  • Cephise Cacho

    • Diamond Light Source

  • Shik Shin

    • Univ of Tokyo
    • University of Tokyo
    • Institute for Solid State Physics, University of Tokyo
    • Univ of Tokyo-Kashiwanoha
    • Institute for Solid State Physics, The University of Tokyo

  • Ryotaro Arita

    • University of Tokyo
    • Univ of Tokyo
    • Department of Applied Physics, The University of Tokyo

  • Keji Lai

    • University of Texas at Austin

  • Takao Sasagawa

    • Tokyo Institute of Technology

  • Takeshi Kondo

    • Univ of Tokyo
    • University of Tokyo
    • Institute for Solid State Physics, University of Tokyo