Volatile 2D electron gas in ultra thin BaTiO<sub>3</sub> films

ORAL

Abstract

We investigate the metallic surface state in ultra-thin films of c-axis oriented BaTiO3 by angle resolved photoemission spectroscopy (ARPES). We find Fermi surface contours derived from the Ti 3d t2g conduction band, with broad spectral features due to enhanced quasi-particle scattering. Oxygen vacancies created in the X-ray beam spot allow for reversible in situ doping control. Up to carrier densities as high as 2 × 1021 cm−3, they retain a charge state of 2+, preventing the formation of localized defect states and charge carrier trapping. Sub-surface oxygen vacancy migration at T > 285 K quenches the surface state. Our findings challenge the implementation of non-volatile room temperature applications based on non-stoichiometric BaTiO3.

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Presenters

  • Simon Moser

    • Lawrence Berkeley Natl Lab
    • Lawrence Berkeley National Laboratory
    • Advanced Light Source, Lawrence Berkeley National Laboratory

Authors

  • Peter Lutz

    • Wurzburg University

  • Simon Moser

    • Lawrence Berkeley Natl Lab
    • Lawrence Berkeley National Laboratory
    • Advanced Light Source, Lawrence Berkeley National Laboratory

  • Vedran Jovic

    • Lawrence Berkeley Natl Lab

  • Young Jun Chang

    • University of Seoul
    • Department of Physics, University of Seoul

  • Roland Koch

    • Lawrence Berkeley Natl Lab
    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab
    • Naval Research laboratory

  • Søren Ulstrup

    • Lawrence Berkeley Natl Lab
    • Lawrence Berkeley National Laboratory
    • Aarhus University
    • Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University

  • Ji Seop Oh

    • Lawrence Berkeley Natl Lab
    • Center for Correlated Electron Systems, Institute for Basic Science

  • Luca Moreschini

    • Lawrence Berkeley Natl Lab

  • Sara Fatale

    • EPFL

  • Marco Grioni

    • EPFL

  • Chris Jozwiak

    • Advanced light source
    • Lawrence Berkeley Natl Lab
    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab
    • Advanced Light Source, Lawrence Berkeley National Laboratory

  • Aaron Bostwick

    • Advanced light source
    • Lawrence Berkeley Natl Lab
    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab
    • Advanced Light Source, Lawrence Berkeley National Laboratory

  • Eli Rotenberg

    • Advanced light source
    • Lawrence Berkeley Natl Lab
    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab
    • Advanced Light Source, Lawrence Berkeley National Laboratory

  • Hendrik Bentmann

    • Wurzburg University
    • Experimentelle Physik VII, Universität Würzburg

  • Friedrich Reinert

    • Wurzburg University
    • Experimentelle Physik VII, Universität Würzburg