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arXiv · 1503.07892

Correlation-driven insulator-metal transition in near-ideal vanadium dioxide films

A. X. Gray·J. Jeong·N. P. Aetukuri·P. Granitzka·Z. Chen·R. Kukreja·D. Higley·T. Chase·A. H. Reid·H. Ohldag·M. A. Marcus·A. Scholl·A. T. Young·A. Doran·C. A. Jenkins·P. Shafer·E. Arenholz·M. G. Samant·S. S. P. Parkin·H. A. Dürr
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Abstract

We use polarization- and temperature-dependent x-ray absorption spectroscopy, in combination with photoelectron microscopy, x-ray diffraction and electronic transport measurements, to study the driving force behind the insulator-metal transition in VO2. We show that both the collapse of the insulating gap and the concomitant change in crystal symmetry in homogeneously strained single-crystalline VO2 films are preceded by the purely-electronic softening of Coulomb correlations within V-V singlet dimers. This process starts 7 K (+/- 0.3 K) below the transition temperature, as conventionally defined by electronic transport and x-ray diffraction measurements, and sets the energy scale for driving the near-room-temperature insulator-metal transition in this technologically-promising material.

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A. X. Gray, J. Jeong, N. P. Aetukuri, P. Granitzka, Z. Chen, R. Kukreja, D. Higley, T. Chase, A. H. Reid, H. Ohldag, M. A. Marcus, A. Scholl, A. T. Young, A. Doran, C. A. Jenkins, P. Shafer, E. Arenholz, M. G. Samant, S. S. P. Parkin, H. A. Dürr. 2015-03-26. Correlation-driven insulator-metal transition in near-ideal vanadium dioxide films. https://doi.org/10.1103/physrevlett.116.116403

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