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

M. Rodriguez-Vega; M. T. Simons; E. Radue; S. Kittiwatanakul; J. Lu; S. A. Wolf; R. A. Lukaszew; I. Novikova; E. Rossi

doi:10.1103/PhysRevB.92.115420

paper

Effect of inhomogeneities and substrate on the dynamics of the metal-insulator transition in VO $_{2}$ thin films

arXiv:1504.05954 · doi:10.1103/PhysRevB.92.115420

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.

10 pages, 15 figures

Effect of inhomogeneities and substrate on the dynamics of the metal-insulator transition in VO2​ thin films

Abstract

Effect of inhomogeneities and substrate on the dynamics of the metal-insulator transition in VO $_{2}$ thin films