Random-resistor network modeling of resistance hysteresis of vanadium dioxide thin films

Abstract

The resistance hysteresis of vanadium dioxide (VO2) is a key feature in revealing mechanisms of a phase transition as well as emerging applications. In this study, a dynamical model based on random-resistor networks is developed to simulate the transport properties of VO2 thin films. The reversible metal–insulator phase transition of each microscopic domain is captured by a modified Landau-type functional. The proposed model enables analysis of not only the formation of conducting filaments driven by an electric field, but also the thermal-driving reversal curves of resistance hysteresis. It is shown that the appearance of a hysteresis loop as well as the aggregation of metallic domains can be tuned via the interactions of each domain with its neighbors and the substrate. The interaction effects are vital for the persistence of metallic domains, which can re-trigger the insulating-to-metallic transition by a subthreshold voltage bias with the delay time much longer than the transition switching time. These results are in agreement with experimental observations and can be helpful in developing VO2-based key components ranging from infrared bolometers to the volatile resistive switches for neuromorphic computing.