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