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

M. W. Haverkort·Z. Hu·A. Tanaka·W. Reichelt·S. V. Streltsov·M. A. Korotin·V. I. Anisimov·H. H. Hsieh·H. -J. Lin·C. T. Chen·D. I. Khomskii·L. H. Tjeng
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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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M. W. Haverkort, Z. Hu, A. Tanaka, W. Reichelt, S. V. Streltsov, M. A. Korotin, V. I. Anisimov, H. H. Hsieh, H. -J. Lin, C. T. Chen, D. I. Khomskii, L. H. Tjeng. 2005-09-14. Orbital-assisted metal-insulator transition in VO$_{2}$. https://doi.org/10.1103/physrevlett.95.196404

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