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Strain-Induced Ferroelectricity in Freestanding SrTiO<sub>3 </sub>Membranes

ORAL

Abstract

SrTiO3 is known to exhibit quantum paraelectricity in which quantum fluctuations suppress ferroelectric ordering at low temperature. Despite the intrinsic paraelectric nature of SrTiO3, epitaxial strain applied via the lattice mismatch in thin-film heterostructures can significantly enhance the ferroelectric transition temperature Tc. Here we utilize freestanding crystalline membranes to extend the lattice control of ferroelectric ordering in SrTiO3. By dissolving a water-soluble buffer layer, we release SrTiO3 films from substrates, and transfer the resulting freestanding membranes onto flexible substrates that can be dynamically stretched into various strain states. Using second harmonic generation microscopy, we probe the ferroelectric phase transition as a function of strain wherein we observe Tc is significantly enhanced by strain. Upon applying 1.5% uniaxial strain, we observe robust room-temperature ferroelectricity with the notable feature of 180° ferroelectric domains using piezoresponse force microscopy. First-principle calculations and molecular dynamics simulations further reveal the structural nature at each given strain state and the order-disorder character of phase transition in strained SrTiO3 membranes.


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Presenters

  • Ruijuan Xu

    Department of Applied Physics, Stanford University, Applied Physics, Stanford University

Authors

  • Ruijuan Xu

    Department of Applied Physics, Stanford University, Applied Physics, Stanford University

  • Jiawei Huang

    School of Science, Westlake University

  • Ed Barnard

    Lawrence Berkeley National Laboratory, The Molecular Foundry, Lawrence Berkeley National Laboratory

  • Seung Sae Hong

    Stanford University, Department of Applied Physics, Stanford University, Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory & Stanford University

  • Ed Wong

    Lawrence Berkeley National Laboratory, The Molecular Foundry, Lawrence Berkeley National Laboratory

  • Varun Harbola

    Department of Physics, Stanford University, Physics, Stanford University

  • Prastuti Singh

    Department of Applied Physics, Stanford University, Applied Physics, Stanford University

  • Bai Yang Wang

    Department of Physics, Stanford University, Physics, Stanford University, Stanford University

  • Shi Liu

    School of Science, Westlake University

  • Harold Hwang

    Institute for Materials and Energy Sciences, Stanford University, Stanford University, Department of Applied Physics, Stanford University, Applied Physics, Stanford University, SIMES, SLAC, Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA, SLAC National Accelerator Lab., Physics, Stanford University, Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory