Transport and microscopic investigations on the electric-pulse-induced phase transition of VO₂ films

We investigated the effect of a strong electric pulse on the insulator-metal phase transition of VO₂ films. As the voltage amplitude increases, we found several jumps of the current value, which are attributable to the multi-level resistance switching. By monitoring the sample with an optical microscope, we observed that the current jumps accompany inhomogeneous developments of metallic area. We argued that the formation of the conducting filaments is responsible for the multi-level switching and the electric-pulse-induced insulator-metal transition of VO₂ films.