Suppression of Metal-Insulator Transition in VO<sub>2</sub> by Interfacial Oxygen Migration

ORAL

Abstract

Oxygen defects are essential building blocks for designing functional oxides with remarkable properties, ranging from electrical and ionic conductivity to magnetism and ferroelectricity. Oxygen defects therefore can profoundly alter crystal and electronic structures and enables emergent phenomena. In this work, we achieved tunable metal-insulator transition (MIT) in oxide heterostructures by inducing interfacial oxygen vacancy migration. We chose VO2-x as a model system due to its near room temperature metal-insulator transition temperature. We found that depositing a TiO2 capping layer on an epitaxial VO2 thin film can effectively suppress the MIT in VO2. We systematically studied the TiO2/VO2 heterostructures by structural and transport measurements, resonant inelastic x-ray scattering, X-ray photoelectron spectroscopy, and first principles calculations and found that that oxygen vacancy migration from TiO2 to VO2 is responsible for the suppression of MIT. Our findings underscore the importance of the interfacial oxygen “diode” effect in determining electronic structure and functionality, and provide new pathways of designing oxide heterostructures for novel ionotronics and computing devices.

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Presenters

  • Qiyang Lu

    • Materials Science and Technology Division, Oak Ridge National Laboratory

Authors

  • Qiyang Lu

    • Materials Science and Technology Division, Oak Ridge National Laboratory

  • Changhee Sohn

    • Materials Science and Technology Division, Oak Ridge National Laboratory
    • Materials Science and Technology Division, Oak Ridge National Lab
    • Materials Sciences and Technology Division, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory

  • Guoxiang Hu

    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • Center for Nanophase Materials and Sciences, Oak Ridge National Laboratory

  • Panchapakesan Ganesh

    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • Oak Ridge National Lab
    • Oak Ridge National Laboratory
    • Center for Nanophase Materials and Sciences, Oak Ridge National Laboratory

  • Paul Kent

    • Oak Ridge National Laboratory
    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • Center for Nanophase Materials and Sciences, Oak Ridge National Laboratory

  • Olle Heinonen

    • Argonne National Laboratory
    • Materials Science Division, Argonne National Laboratory
    • Materials Science Division, Argonne National Laboratory, Lemont, Illinois, USA

  • Gyula Eres

    • Center for Nanophase Materials and Sciences, Oak Ridge National Laboratory

  • Ho Nyung Lee

    • Materials Science and Technology Division, Oak Ridge National Laboratory
    • Materials Sciences and Technology Division, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory