Strain-induced oxygen vacancies in ultrathin epitaxial CaMnO$_{\mathrm{3}}$ films

ORAL

Abstract

Dynamic control of strain-induced ionic defects in transition-metal oxides is considered to be an exciting new avenue towards creating materials with novel electronic, magnetic and structural properties. Here we use atomic layer-by-layer laser molecular beam epitaxy to synthesize high-quality ultrathin single-crystalline CaMnO$_{\mathrm{3}}$ films with systematically varying coherent tensile strain. We then utilize a combination of high-resolution soft x-ray absorption spectroscopy and bulk-sensitive hard x-ray photoemission spectroscopy in conjunction with first-principles theory and core-hole multiplet calculations to establish a direct link between the coherent in-plane strain and the oxygen-vacancy content. We show that the oxygen vacancies are highly mobile, which necessitates an in-situ-grown capping layer in order to preserve the original strain-induced oxygen-vacancy content. Our findings open the door for designing and controlling new ionically active properties in strongly-correlated transition-metal oxides.

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Authors

  • Ravini Chandrasena

    Department of Physics, Temple University, Philadelphia, PA, USA, Department of Physics, Temple University, Phialdelphia, PA, USA

  • Weibing Yang

    Department of Physics, Temple University, Philadelphia, PA, USA

  • Qingyu Lei

    Temple University, Department of Physics, Philadelphia PA 19122, Department of Physics, Temple University, Philadelphia, PA, USA

  • Mario Delgado-Jaime

    Inorganic Chemistry & Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands

  • Frank de Groot

    Inorganic Chemistry & Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands

  • Elke Arenholz

    Advanced Light Source, Lawrence Berkeley National Laboratory, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

  • Keisuke Kobayashi

    Materials Sciences Research Center, Japan Atomic Energy Agency, Sayo, Japan

  • Ulrich Aschauer

    Materials Theory, ETH Zurich, Zurich, Switzerland

  • Nicola Spaldin

    Materials Theory, ETH Zurich, Zurich, Switzerland

  • Xiaoxing Xi

    Temple University, Temple University, Department of Physics, Philadelphia PA 19122, Physics Department, Temple University, Philadelphia PA 19122, USA, Department of Physics, Temple University, Philadelphia, PA, USA, Temple Univ

  • Alexander Gray

    Department of Physics, Temple University, Philadelphia, PA, USA, Department of Physics, Temple University, Phialdelphia, PA, USA