Effect of inhomogeneities and substrate on the dynamics of the metal-insulator transition in VO${}_2$ thin films

Abstract

We study the thermal relaxation dynamics of VO${}_2$ films after the ultrafast photo-induced metal-insulator transition for two VO${}_2$ film samples grown on Al${}_2$O${}_3$ and TiO${}_2$ substrates. We find two orders of magnitude difference in the recovery time (a few ns for the VO${}_2$/Al${}_2$O${}_3$ sample vs. hundreds of ns for the VO${}_2$/TiO${}_2$ sample). We present a theoretical model that accurately describes the MIT thermal properties and interpret the experimental measurements. We obtain quantitative results that show how the microstructure of the VO${}_2$ film and the thermal conductivity of the interface between the VO${}_2$ film and the substrate affect long time-scale recovery dynamics. We also obtain a simple analytic relationship between the recovery time-scale and some of the film parameters.

arXiv comment10 pages, 15 figures

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Cited by in corpus (1)

• Evidence for bootstrap percolation dynamics in a photo-induced phase transition