Direct observation of the electrically triggered Insulator-Metal transition in V3O5 far below the transition temperature

TL;DR

This study demonstrates electric-field-induced resistive switching and oscillations in V3O5 at room temperature, revealing the formation of metallic filaments and phase transitions below the material's natural transition temperature.

Contribution

It provides direct optical evidence of electrically triggered insulator-metal transition and filament formation in V3O5 at sub-transition temperatures, combining experimental imaging and simulations.

Findings

Resistive switching occurs at 120 K below Tc.

Metallic filaments form during switching, confirmed by optical imaging.

Oscillatory spiking linked to negative differential resistance regime.

Abstract

Resistive switching is one of the key phenomena for applications such as nonvolatile memories or neuromorphic computing. V3O5, a compound of the vanadium oxide Magn\'eli series, is one of the rare materials to exhibit an insulator-metal transition (IMT) above room temperature (Tc ~ 415 K). Here we demonstrate both static dc resistive switching (RS) and fast oscillatory spiking regimes in V3O5 devices at room temperature (120 K below the phase transition temperature) by applying an electric field. We use operando optical imaging to track a reflectivity change during the RS and find that a percolating high temperature metallic phase filament is formed. This demonstrates that the electrically induced RS triggers the phase transition. Furthermore, we optically capture the spiking oscillations that we link to the negative differential resistance regime and find the filament forms and dissolves via a periodic spatio-temporal instability that we describe by numerical simulations.