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Interfacial engineering ferroelectricity in two-dimensional CuInP<sub>2</sub>S<sub>6</sub>

ORAL

Abstract

CuInP2S6 (CIPS), a layered van der Waals material, has been regarded as a promising candidate for realizing two-dimensional (2D) ferroelectrics. However, its high mobility of Cu ions makes it challenging to achieve precise domain control and obtain high Curie temperature (TC). In this collaborative work, we find that placing CIPS on PbTiO3 (PTO) substrate is helpful to overcome these challenges. Employing first-principles density functional theory calculation of monolayer CIPS on PTO substrate, we find that accumulated charges on the PTO surface provide an intrinsic field that tilts the free energy well of CIPS and help promote the polar alignment in CIPS. Meanwhile, the PTO substrate modulates the atomic structure of CIPS and increases the energy barrier for switching polarization. As a result, the Monte Carlo (MC) simulation shows that the Curie temperature is significantly increased from 400 K to 650 K. These theoretical calculations agree with experimental measurements. This study points to a new strategy to engineer the nanoscale domain structure and piezoelectricity of the 2D ferroelectrics for technological implementation, such as nonvolatile memories, nanoelectronics and optoelectronics.

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Presenters

  • Du Li

    Washington University in St. Louis

Authors

  • Du Li

    Washington University in St. Louis

  • Kun Wang

    University of Nebraska - Lincoln, Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Department of Physics and Astronomy & Nebraska Center for Materials and NanoscienceUniversity of Nebraska - Lincoln, Physics and Astronomy, University of Nebraska-Lincoln

  • Jia Wang

    Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, University of Nebraska-Lincoln, Department of Physics and Astronomy & Nebraska Center for Materials and NanoscienceUniversity of Nebraska-Lincoln, Physics and Astronomy, University of Nebraska-Lincoln

  • Yifei Hao

    University of Nebraska - Lincoln, Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience,University of Nebraska - Lincoln, Physics and Astronomy, University of Nebraska-Lincoln

  • Hailey Anderson

    University of Nebraska-Lincoln

  • Xia Hong

    Physics and Astronomy, University of Nebraska-Lincoln, Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln

  • Li Yang

    Washington University, St. Louis