Strain-Induced High Polarization of a KNbO3 Thin Film on a Single Crystalline Rh Substrate

Authors

  • Geunhee Lee,

    1. Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico
    2. Materials Science Division, Argonne National Laboratory, Argonne, IL
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  • Young-Han Shin,

    Corresponding author
    1. Departments of Physics and Chemistry and EHSRC, University of Ulsan, Ulsan, Korea
    • Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico
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  • Jong Yeog Son

    Corresponding author
    1. Department of Applied Physics, College of Applied Science, Kyung Hee University, Suwon, Korea
    • Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico
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Authors to whom correspondence should be addressed. e-mails: hoponpop@ulsan.ac.kr and jyson@khu.ac.kr

Abstract

High-quality epitaxial KNbO3 (KNO) thin films grown on single crystalline (001) Rh substrates exhibited a tetragonally strained structure with a c/a ratio of 1.04. The strained KNO thin film showed a high remanent polarization of 42 μC/cm2 with a coercive electric field of 170 kV/cm. Based on the density functional theory calculations, the increase in polarization and piezoelectricity in the tetragonally and compressively strained KNO thin film is primarily attributed to the faster increase of the displacement of Nb ions than the decrease in the Born effective charge.

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