Ferroelectric switching of a two-dimensional metal

ORAL

Abstract

In its 3D form the semimetal WTe2 has a polar space group, whereas an isolated monolayer of WTe2 is centrosymmetric. We find that when exfoliated down to two- or three-layer thickness, WTe2 exhibits a spontaneous out-of-plane electric polarization, while the monolayer does not. The polarization persists to room temperature and can be switched by a perpendicular electric field using graphite gate electrodes located above and below the sheet. We directly detect and quantify the polarization using graphene as an electric-field sensor. The polarization state can also be distinguished via the in-plane conductivity. The ferroelectricity persists even when the material is metallic in the plane; this is possible because the few-layer WTe2 is so thin that the applied electric field penetrates it.

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Presenters

  • Wenjin Zhao

    University of Washington

Authors

  • Wenjin Zhao

    University of Washington

  • Zaiyao Fei

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

  • Tauno Palomaki

    University of Washington

  • Bosong Sun

    University of Washington

  • Moira K Miller

    University of Washington, University of California, Davis

  • Zhiying Zhao

    Oak Ridge National Laboratory

  • Jiaqiang Yan

    Oak Ridge National Laboratory (USA), Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge National Laboratory, Materials Science and Technology, Materials Science and Technology, Oak Ridge National Lab, Materials Science and Engineering, The University of Tennessee

  • Xiaodong Xu

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

  • David Henry Cobden

    University of Washington