Local Electronic Structure at Oxide-Oxide Interfaces Probed by Atomic Resolution Electron Energy Loss Spectroscopy

ORAL

Abstract

We report an atomic resolution study of the electronic structure of 12 x 4 LaMnO$_{3}$-SrMnO$_{3}$ and 2 x 2 LaMnO$_{3}$-SrTiO$_{3}$ superlattices and their interfaces grown on SrTiO$_{3}$ by EELS. We correlated the interfacial electronic structure with the interfacial atomic structure using atomic resolution Z-contrast STEM using an electron probes of $<$0.1 nm. The oxide superlattices were synthesized using molecular beam epitaxy. We measured the site-specific unoccupied states of oxygen atoms and transition metals. In the LMO-SMO system we found extra states (holes) near the Fermi level and their dependence on abruptness of interface. In LMO-STO, we will present evidence of site-dependent electronic structure of oxygen and the Mn valence based on the L-edge ratios.

*Supported by DOE BES

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Authors

  • Amish Shah

    • Dept. of Mat. Sci. Eng., Univ. of Illinois, Urbana-Champaign

  • Q. M. Ramasse

    • National Center for Electron Microscopy, Lawrence Berkeley National Laboratory
    • National Center for Electron Microscopy, Lawrence-Berkeley National Laboratory

  • Steven May

    • Materials Science Division, Argonne National Laboratory
    • Argonne National Lab

  • J.G. Wen

    • Materials Res. Lab., Univ. of Illinois, Urbana-Champaign

  • J.N. Eckstein

    • Dept. of Physics, Univ. of Illinois, Urbana-Champaign

  • Anand Bhattacharya

    • Argonne National Laboratory
    • Materials Science Division, Argonne National Laboratory
    • Center for Nanoscale Materials and Materials Science Division, Argonne National Laboratory
    • Argonne National Lab

  • J.M. Zuo

    • Dept. of Materials Science and Engineering and Materials Research Laboratory, University of Illinois at Urbana-Champaign
    • Dept. of Mat. Sci. Eng., Univ. of Illinois, Urbana-Champaign