Microwave Impedance Microscopy of WTe2

ORAL

Abstract

WTe2 is a van der Waals layered material that behaves as a 2D topological insulator when exfoliated down to a monolayer, supporting edge modes that should be topologically protected. Microwave impedance microscopy (MIM) is a technique that allows real-space mapping of conductivity with a resolution of < 50 nm, and is thus a powerful tool for studying these edge modes that reveals many features that are not accessible to transport measurements alone. Using MIM we observe that the edge is gapless and the edge conduction path conforms to microscopic corners and cracks in the edge and features internal to the monolayer flake. This is consistent with their topological nature and has important consequences for interpreting transport measurements and for making devices employing the 1D helical modes.We also study the behavior of multilayer WTe2, twisted bilayer WTe2, and monolayer WTe2 combined with other materials, such as different capping layers and 2D ferromagnets.

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Presenters

  • Joshua Kahn

    University of Washington

Authors

  • Joshua Kahn

    University of Washington

  • Yanmeng Shi

    School of Physics and Astronomy, University of Manchester, Department of Physics and Astronomy, University of California, Riverside, University of California, Riverside

  • Zaiyao Fei

    University of Washington, Physics, University of Washington, Seattle, Department of Physics, University of Washington

  • Brian A Francisco

    University of California, Riverside

  • Ben Niu

    University of California, Riverside

  • Xiaodong Xu

    University of Washington, Department of Physics, University of Washington, University of Washington, Seattle

  • Yongtao Cui

    University of California, Riverside

  • David Henry Cobden

    University of Washington