Influence of the Termination Layer on the Electronic Properties of LaMnO$_{3}$ / SrTiO$_{3}$ Interfaces

ORAL

Abstract

We examine charge leakage at the interface between two oxide materials with different B- site cations: SrTiO$_{3}$ (STO), a band insulator, and LaMnO$_{3}$ (LMO)- a Mott insulator-, or La $_{0.7}$Sr $_{0.3}$MnO$_{3}$ (LSMO) a metal. This system incorporates a polar discontinuity at the interface, as in SrTiO$_{3}$ (STO) /LaAlO$_{3}$ (LAO), which is modulated by the Sr content. Using combined atomic column resolution imaging and spectroscopy we provide direct evidence for a change of the Ti oxidation state from 4$^{+}$ to 3$^{+}$ at the interface in LMO/STO, resulting from the transfer of electrons from the LMO manganite into the titanate layer. This change is also observed for samples with LSMO and appears to be dependent on the layer thickness ratio as in the polarity conflict scenario. Possible explanations are discussed in terms of the composition of the termination plane of the manganite. Work at UCM supported by MAT2008 6517. Research at ORNL sponsored by US DOE

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Authors

  • J. Santamaria

    • Universidad Complutense de Madrid
    • GFMC, Universidad Complutense de Madrid, Madrid 28040, Spain
    • Universidad Complutense de Madrid, Spain

  • J. Garcia-Barriocanal

    • GFMC, Universidad Complutense de Madrid, Madrid 28040, Spain

  • F.Y. Bruno

    • GFMC, Universidad Complutense de Madrid, Madrid 28040, Spain

  • Z. Sefrioui

    • GFMC, Universidad Complutense de Madrid, Madrid 28040, Spain
    • Universidad Complutense de Madrid, Spain

  • A. Rivera-Calzada

    • GFMC, Universidad Complutense de Madrid, Madrid 28040, Spain

  • N. M. Nemes

    • GFMC, Universidad Complutense de Madrid, Madrid 28040, Spain

  • C. Leon

    • GFMC, Universidad Complutense de Madrid, Madrid 28040, Spain

  • M. Garcia-Hernandez

    • Instituto de Ciencia de Materiales de Madrid
    • Instituto de CC de Materiales de Madrid ICMM- CSIC. Madrid 28049, Spain.

  • M. Varela

    • Oak Ridge National Laboratory, Oak Ridge TN 37831
    • Materials Science \& Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
    • Oak Ridge National Laboratory
    • Oak Ridge Natl. Lab.

  • S. J. Pennycook

    • Oak Ridge National Laboratory
    • Oak Ridge National Laboratory, Oak Ridge TN 37831
    • Materials Science \& Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
    • Oak Ridge Natl. Lab.