Direct Observation of the Electrically Triggered Insulator-Metal Transition in V3O5 Far below the Transition Temperature

Resistive switching is of the key phenomena for applications such as nonvolatile memories or neuromorphic computing. V3O5, a compound of the vanadium oxide Magne ' li series, is one of the rare materials to exhibit an insulator-metal transition above room temperature (T-c similar to 415 K). The switching mechanisms in this material are still not clear. Here, we demonstrate both static dc volatile resistive switching and fast oscillatory spiking regimes in V3O5 devices at room temperature (120 K below the phase transition temperature) by applying an electric field. We couple electrical measurements, operando optical imaging, and infrared measurements to track the reflectivity change and the temperature of a device during the resistive switching. We find that the resistive switching starts via thermal runaway deep in the insulating state and triggers the phase transition with the formation of a filament of the high-temperature phase. Furthermore, we capture optically and thermally the spiking oscillations that we link to the negative differential resistance regime and find the filament forms and dissolves via a periodic spatiotemporal instability that we describe by numerical simulations. Our studies play an important role in understanding the volatile resistive switching mechanisms and demonstrate that V3O5 can be a key vanadium oxide for neuromorphic computing.