Strain tuning of ferroelectricity in KNbO<sub>3</sub>

ORAL

Abstract

The coupling between ferroelectric and ferroelastic order parameters in transition metal oxide systems offer unique opportunities to employ strain as a tuning parameter of polar order at the nanoscale limit with large scale technological implications. KNbO3 is an archetypal ferroelectric with a rich structural phase diagram in the bulk and provides the possibility of stabilising non-trivial phases through strain-engineering which are otherwise thermodynamically inaccessible. The ability to grow KNbO3 thin films by sub-oxide molecular beam epitaxy allows the application of large strains with a high degree of control in epitaxial thin films. The new stabilised structure is probed through temperature dependent second harmonic generation, synchrotron-based x-ray reciprocal space mapping and transmission electron microscopy which reveals a giant enhancement in ferroelectric Tc, polarisation and nonlinear optical coefficients even surpassing PbTiO3 and BaTiO3. Thermodynamic phase field simulations and density functional modeling also supports the experimentally achieved strain-phase diagram for KNbO3.

*Department of Energy

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Presenters

  • Sankalpa Hazra

    • The Pennsylvania State University

Authors

  • Sankalpa Hazra

    • The Pennsylvania State University

  • Tobias Schwaigert

    • Cornell University

  • Aiden Ross

    • The Pennsylvania State University

  • Utkarsh Saha

    • The Pennsylvania State University

  • salva Salmani-Rezaie

    • Ohio state university
    • The Ohio State University

  • Victor Trinquet

    • Université catholique de Louvain

  • Saugata Sarker

    • The Pennsylvania State University
    • Pennsylvania State University

  • tatiana Kuznetsova

    • Pennsylvania State University
    • The Pennsylvania State University

  • Roman Engel-Herbert

    • Paul Druide Institute for Solid state electronics (PDI)
    • Paul Drude Institute for Solid State Electronics

  • Matthew R Barone

    • Cornell University
    • Department of Materials Science and Engineering, Cornell University

  • Gian-Marco Rignanese

    • Universite catholique de Louvain

  • David A Muller

    • Cornell University

  • Vladimir A Stoica

    • Pennsylvania State University

  • Long-Qing Chen

    • The Pennsylvania State University
    • Pennsylvania State University

  • Darrell G Schlom

    • Cornell University
    • Department of Materials Science and Engineering, Cornell University

  • Venkatraman Gopalan

    • Pennsylvania State University
    • The Pennsylvania State University