Modulating metal-insulator transitions in VO<sub>X</sub> by tuning oxygen stoichiometry

ORAL

Abstract

Thermally driven metal-insulator transitions (MITs) in vanadium oxides (VOX) have been of special interest in fundamental physics and oxide electronics. The existence of multi-valence states of vanadium leads to a complicated vanadium-oxygen phase diagram. Moreover, for thin films, finite size or strain effects can alter the physical and thermodynamic properties of the V-O system. Therefore, precise oxygen stoichiometry control in these oxide films remains an outstanding issue and a clear phase stability diagram has not yet been found. We demonstrate a gas evolution technique to precisely modify the oxygen stoichiometry in VOX thin films grown on sapphire substrates. By carefully tuning the temperature-oxygen partial pressure-time relationship, controlled phase evolution between VO2, V2O3 and Magnéli phases (VnO2n-1) was achieved, along with the detailed characterization of their electrical transport and structural properties. Moreover, we show that high quality films, with well-defined MITs can be synthesized this way.

*This work was supported by the AFOSR grant FA9550-14-1-0202, funded by the Vannevar Bush Faculty Fellowship program and funded by the Office of Naval Research through grant N00014-15-1-2848. J. del Valle acknowledges support from Fundación Ramón Areces.

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Presenters

  • Minhan Lee

    • Department of Physics and Center for Advanced Nanoscience, University of California - San Diego

Authors

  • Minhan Lee

    • Department of Physics and Center for Advanced Nanoscience, University of California - San Diego

  • Yoav Kalcheim

    • University of California San Diego
    • Department of Physics and Center for Advanced Nanoscience, University of California - San Diego
    • University of California, San Diego
    • Department of Physics and Center for Advanced Nanoscience, University of California San Diego
    • Department of Physics, University of California San Diego

  • Javier del Valle

    • Department of Physics and Center for Advanced Nanoscience, University of California - San Diego
    • Department of Physics and Center for Advanced Nanoscience, University of California San Diego
    • Department of Physics, University of California San Diego

  • Ivan Schuller

    • Physics, University of California, San Diego
    • University of California San Diego
    • Department of Physics and Center for Advanced Nanoscience, University of California - San Diego
    • Physics, UC San Diego
    • University of California, San Diego
    • Physics and Astronomy, University of California San Diego
    • Department of Physics and Center for Advanced Nanoscience, University of California San Diego
    • Department of Physics and Center for Advanced Nanoscience, University of California, San Diego
    • Department of Physics, University of California San Diego