Modulating metal-insulator transitions in VOX 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.

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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