Band alignments at the interface of complex oxides

ORAL

Abstract

The realization of a two-dimensional electron gas at the SrTiO$_3$/LaAlO$_3$ interface has spurred interest in the development of electronic devices based on complex oxides. In the design of such devices it is crucial to know the band alignment at the interface of the different oxides, a key quantity that governs carrier barrier heights and carrier confinement. Reported values for the valence-band alignment at the SrTiO$_3$/LaAlO$_3$ interface vary by more than 1 eV. Using first-principles calculations based on a hybrid functional we calculate the band alignment at the interface between various complex oxides, including the band insulators SrTiO$_3$, SrZrO$_3$, LaAlO$_3$, CaTiO$_3$, and GaAlO$_3$ and the Mott insulators GdTiO$_3$ and YTiO$_3$. This choice of materials allows us to analyze the effects of cation size, lattice parameters, band gaps, and lattice orientation on the band alignment.

*This work was supported by NSF and ARO.

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Authors

  • Lars Bjaalie

    • University of California Santa Barbara

  • Anderson Janotti

    • Materials Department, University of California Santa Barbara
    • University of California, Santa Barbara Materials Department
    • University of California Santa Barbara
    • University of California, Santa Barbara

  • Chris Van de Walle

    • University of California at Santa Barbara
    • Materials Department, University of California, Santa Barbara
    • Materials Department, University of California Santa Barbara
    • University of California, Santa Barbara
    • University of California, Santa Barbara Materials Department
    • University of California Santa Barbara
    • Materials department and materials Research Lab, University of California Santa Barbara, California 93106-5050, USA
    • Materials Department, University of California at Santa Barbara