APS Logo

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).

–

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