Volatile 2D electron gas in ultra thin BaTiO3 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