Van-der-Waals layered ferroelectric CuInP<sub>2</sub>S<sub>6</sub> I: a quadruple-well potential

ORAL

Abstract

CuInP2S6 (CIPS) is a van der Waals solid that is ferrielectric below room temperature and has polarization in the stacking direction. Using density-functional-theory calculations, we discovered that, instead of the usual double-well potential, CIPS features a unique quadruple-well potential, with two low-polarization and two high-polarization states, with the latter corresponding to large Cu displacements to the layer surfaces, where they bond to the adjacent layers.[1] The quadruple well is tunable by strain, which can eliminate one or the other of the polar states. Quantum molecular dynamics shed light on the nature of polarization switching in the CIPS environment. The predicted features have been verified by experiments utilizing scanning probe microscopy (next abstract, Maksymovych et al.). The new results and the propensity of CIPS for ionic substitution opens new opportunities to control and generate ferroelectric properties in layered materials.
[1] J. A. Brehm et al. “Tunable quadruple-well ferroelectric van-der-Waals crystals”, Nature Mater., in press.

*Work at CNMS, ORNL supported by DOE BES MSE. At Vanderbilt MSE Div. DE-FG02-09ER46554; LT partially funded by IoP, CAS, Beijing.

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Presenters

  • Lei Tao

    • Vanderbilt University
    • Chinese Academy of Sciences

Authors

  • Lei Tao

    • Vanderbilt University
    • Chinese Academy of Sciences

  • John A Brehm

    • Vanderbilt University

  • Sabine M. Neumayer

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Andrew O’Hara

    • Vanderbilt University

  • Marius Chyasnavichus

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Michael Susner

    • UES, Inc.
    • Aerospace Systems Directorate, Air Force Research Laboratory
    • Oak Ridge National Lab
    • Air Force Research Laboratory

  • Michael McGuire

    • Oak Ridge National Laboratory
    • Materials Science and Technology Division, Oak Ridge National Laboratory
    • Oak Ridge National Lab
    • Materials Science Division, Oak Ridge National Laboratory

  • Sergei V. Kalinin

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Stephen Jesse

    • Oak Ridge National Laboratory
    • Oak Ridge National Lab
    • University of Tennessee

  • Panchapakesan Ganesh

    • Oak Ridge National Laboratory

  • Sokrates T Pantelides

    • Department of Physics and Astronomy, Vanderbilt Univ
    • Department of Physics and Astronomy, Vanderbilt University
    • Vanderbilt University

  • Petro Maksymovych

    • Center for Nanophase Materials Sciences, Oak Ridge National Lab
    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Nina Balke

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory