Electrical Control over Volatile Mott Switching through Non-Volatile Memory Effects

Abstract

Vanadium Dioxide (VO2) and Vanadium Sesquioxide (V2O3) are Mott insulators that undergo an Insulator-to-Metal Transition (IMT) at ~340K and ~160K, respectively, manifested as an orders-of-magnitude reduction in their electrical resistance. These transitions provide the physical basis for their Volatile Resistive Switching (VRS) behavior, making them promising candidates for threshold-switching devices. Here, we show that the volatile switching in these materials can be strongly affected by non-volatile processes associated with the creation and annihilation of the conducting filament. These processes give rise to pronounced memory effects in which the initial switching voltage substantially exceeds that of subsequent cycles. We identify two distinct mechanisms underlying this behavior in different thermal regimes. In the phase-coexistence regime, a memory effect is observed in V2O3, arising from the spatial redistribution of metallic and insulating domains. Well below the hysteresis regime, an additional electroforming-like memory effect is observed in both VO2 and V2O3 which is attributed to the formation and/or migration of defects under the influence of a high electric field and a current surge associated with the IMT-driven switching. Using a protective internal resistor and a multi-step writing protocol, this normally destructive process can be harnessed to tune the switching voltage and power over a wide temperature range. These results demonstrate a route toward controlled programming of switching parameters in IMT-based resistive switching devices.