Tunability of the Metal–Insulator Transition in VO<sub>2</sub>/TiO<sub>2</sub> Heterostructures

ORAL

Abstract

The metal–insulator transition in strongly correlated vanadium dioxide (VO2) has attracted considerable interest. It has been shown that formation of oxygen vacancies (VO) in VO2 can suppress this MIT completely without any structural transition. Since VO can be introduced via tuning the thickness or type of capping oxide layers, in this work, we studied the control of MIT in VO2 by interfacing with a TiO2 capping layer. Using a combined approach with experimental measurements and theoretical calculations, we find that a TiO2 capping layer on an epitaxial VO2 thin film suppresses the MIT in VO2. Density functional theory (DFT) calculations, benchmarked against more accurate many-body quantum Monte Carlo (QMC) calculations, provide information on the VO formation energy profile across the VO2/TiO2 interface. It is found that the VO2/TiO2 interface can facilitate the VO migration from TiO2 to VO2, and it is this migration that is responsible for the suppression of MIT in VO2. Our study highlights the crucial role of VO introduced by a capping layer in tuning the MIT in epitaxial VO2 thin films, which is useful for developing advanced electronic and iontronic devices.

*This work was supported by the Center for Predictive Simulation of Functional Materials, a DOE-BES center.

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Presenters

  • Guoxiang Hu

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

Authors

  • Guoxiang Hu

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

  • Qiyang Lu

    • Materials Science and Technology Division, Oak Ridge National Laboratory

  • Ilkka Kylanpaa

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

  • Jaron Krogel

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

  • 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

  • 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