Imaging Conductive Edge States in Monolayer WTe2

ORAL

Abstract

The quantum spin Hall (QSH) effect occurs in two-dimensional topological insulators where helical edge states circulate the insulating bulk. Recent experiments have reported QSH signatures in monolayer WTe2. In our experiment, we use microwave impedance microscopy (MIM), a scanning probe technique that senses materials’ local electrical properties, to directly image the edge states in monolayer WTe2, and correlate their behaviors with electrical transport. Conductive states are clearly resolved at edges of the monolayer WTe2. They remain conductive when the bulk carrier density is tuned through the bandgap, but become only slightly weaker at high magnetic field while the conductance measured by transport is strongly suppressed. The edge conduction can be resolved up to 100 K in temperature when the bulk becomes conductive. In addition, we also observe conduction features in the bulk of the WTe2 flake. We will discuss the implications of these observations on the topological properties of monolayer WTe2.

Presenters

  • Yongtao Cui

    Department of Physics & Astronomy, University of California, Riverside, Univ of California, Riverside

Authors

  • Yanmeng Shi

    Univ of California, Riverside, Physics, University of California, Riverside

  • Joshua Kahn

    Univ of Washington

  • Zaiyao Fei

    Univ of Washington, Physics, University of Washington

  • Brian Francisco

    Univ of California, Riverside

  • Ben Niu

    Univ of California, Riverside

  • Xiaodong Xu

    University of Washington, Univ of Washington, Physics, Univ of Washington, Department of Physics, University of Washington, Physics, University of Washington, Physics, and Materials Science and Engineering, Univ of Washington, Department of Physics, University of Washington - Seattle

  • David Cobden

    Univ of Washington, Department of Physics, University of Washington, University of Washington, Physics, University of Washington

  • Yongtao Cui

    Department of Physics & Astronomy, University of California, Riverside, Univ of California, Riverside