STM/S study of edge states in a large energy gap near the step edges on the surface of ZrTe$_{\mathrm{5}}$

ORAL

Abstract

Despite considerable theoretical efforts in predicting large-gap two-dimensional topological insulator candidates, none of them have been experimentally demonstrated to have a full gap, which is crucial for quantum spin Hall effect. Here, we use low temperature scanning tunneling microscopy/spectroscopy (STM/S) to study the single crystal of ZrTe$_{\mathrm{5}}$, which has a qusi-2D layered structure and is a potential large-gap 2D TI predicted by calculations. The results reveal that ZrTe$_{\mathrm{5}}$ hosts a large full energy gap of \textasciitilde 100 meV on the surface and a nearly constant density of states within the entire gap at the monolayer step edge. These features are well reproduced by our first-principles calculations, which point to the topologically nontrivial nature of the edge states. The gap position in Brillouin zone and the band structure are demonstrated by angle-resolved photoemission spectroscopy. We also make a study for HfTe$_{\mathrm{5\thinspace }}$by using STM/S, which confirms the same behaviors as on ZrTe$_{\mathrm{5}}$.

–

Authors

  • Rui Wu

    • Institute of Physics, Chinese Academy of Sci (CAS) & Department of Physics, Tsinghua University, China

  • Xiong Huang

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Ruizhe Liu

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Jiaxin Yin

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Junzhang Ma

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Simin Nie

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Lingxiao Zhao

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Bingbing Fu

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Pierre Richard

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Genfu Chen

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Zhong Fang

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Xi Dai

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Hongming Weng

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Tian Qian

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Hong Ding

    • Institute of Physics, Chinese Academy of Sci (CAS)

  • Shuheng Pan

    • Institute of Physics, Chinese Academy of Sci (CAS) & Department of Physics and Texas Center for Superconductivity, University of Houston, USA