Orbital-assisted metal-insulator transition in VO$_{2}$

ORAL

Abstract

We found direct experimental evidence for an orbital switching in the V $3d$ states across the metal-insulator transition in VO$_{2}$. We have used soft-x-ray absorption spectroscopy at the V $L_{2,3}$ edges as a sensitive local probe, and have determined quantitatively the orbital polarizations. These results strongly suggest that, in going from the metallic to the insulating state, the orbital occupation changes in a manner that charge fluctuations and effective band widths are reduced, that the system becomes more 1-dimensional and more susceptible to a Peierls-like transition, and that the required massive orbital switching can only be made if the system is close to a Mott insulating regime.

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Authors

  • M.W. Haverkort

    • II. Physikalisches Institut, Universit{\"a}t zu K{\"o}ln, Germany

  • Z. Hu

    • II. Physikalisches Institut, Universit{\"a}t zu K{\"o}ln, Germany

  • A. Tanaka

    • Department of Quantum Matter, ADSM, Hiroshima University, Japan

  • W. Reichelt

    • Institut f\"{u}r Anorganische Chemie, Technische Universit\"{a}t Dresden, Germany

  • S. V. Streltsov

    • Institute of Metal Physics, Ekaterinburg, Russia

  • M. A. Korotin

    • Institute of Metal Physics, Ekaterinburg, Russia

  • V. I. Anisimov

    • Institute of Metal Physics, Ekaterinburg, Russia

  • H. H. Hsieh

    • Chung Cheng Institute of Technology, Taoyuan, Taiwan

  • H.-J. Lin

    • National Synchrotron Radiation Research Center, Hsinchu, Taiwan

  • C. T. Chen

    • National Synchrotron Radiation Research Center, Hsinchu, Taiwan

  • D. I. Khomskii

    • II. Physikalisches Institut, Universit{\"a}t zu K{\"o}ln, Germany

  • L. H. Tjeng

    • II. Physikalisches Institut, Universit{\"a}t zu K{\"o}ln, Germany