Band alignment in LaAlO3/SrTiO3 oxide heterostructures inferred from hard x-ray photoelectron spectroscopy

G. Berner, A. Müller, F. Pfaff, J. Walde, C. Richter, J. Mannhart, S. Thiess, A. Gloskovskii, W. Drube, M. Sing, and R. Claessen
Phys. Rev. B 88, 115111 – Published 6 September 2013

Abstract

We present a detailed study of the electronic structure and band alignment in LaAlO3/SrTiO3 oxide heterostructures by hard x-ray photoelectron spectroscopy. Our spectroscopic measurements find no evidence for the strong potential gradient within the polar LaAlO3 film predicted by band theory. Due to the high interface sensitivity of the method, we are further able to determine the valence band offset between the LaAlO3 film and the SrTiO3 substrate, which is found to be independent of the number of LAO overlayers. Finally, we discuss several explanations for the apparent absence of the built-in field in ex situ prepared LaAlO3/SrTiO3 heterostructures.

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  • Received 3 July 2013

DOI:https://doi.org/10.1103/PhysRevB.88.115111

©2013 American Physical Society

Authors & Affiliations

G. Berner1, A. Müller1, F. Pfaff1, J. Walde1, C. Richter2,3, J. Mannhart3, S. Thiess4, A. Gloskovskii4, W. Drube4, M. Sing1, and R. Claessen1,*

  • 1Physikalisches Institut and Röntgen Center for Complex Materials Systems (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
  • 2Institute of Physics, Universität Augsburg, Electronic Correlations and Magnetism, Experimentalphysik VI, Universitätsstraße 1, D-86135 Augsburg, Germany
  • 3Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany
  • 4DESY Photon Science, Deutsches Elektronen-Synchrotron, D-22603 Hamburg, Germany

  • *claessen@physik.uni-wuerzburg.de

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Vol. 88, Iss. 11 — 15 September 2013

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