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Evidence for a Structurally-driven Insulator-to-metal Transition in VO2: a View from the Ultrafast Timescale

A. Cavalleri·Th. Dekorsy·H. H. Chong·J. C. Kieffer·R. W. Schoenlein
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Abstract

We apply ultrafast spectroscopy to establish a time-domain hierarchy between structural and electronic effects in a strongly-correlated electron system. We discuss the case of the model system VO2, a prototypical non-magnetic compound that exhibits cell doubling, charge localization and a metal-insulator transition below 340 K. We initiate the formation of the metallic phase by prompt hole photo-doping into the valence band of the low-T insulator. The I-M transition is however delayed with respect to hole injection, exhibiting a bottleneck timescale that corresponds to half period of the phonon connecting the two crystallographic phases. This experiment indicates that this controversial insulator may have important band-like character.

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A. Cavalleri, Th. Dekorsy, H. H. Chong, J. C. Kieffer, R. W. Schoenlein. 2004-03-08. Evidence for a Structurally-driven Insulator-to-metal Transition in VO2: a View from the Ultrafast Timescale. https://doi.org/10.1103/physrevb.70.161102

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