Mott-transition-based RRAM

Resistance random-access memory (RRAM) is a promising candidate for both the next-generation non-volatile memory and the key element of neural networks. In this article, different types of Mott-transition (the transition between the Mott insulator and metallic states) mechanisms and Mott-transition-based RRAM are reviewed. Mott insulators and some related doped systems can undergo an insulator-to-metal transition or metal-to-insulator transition under various excitation methods, such as pressure, temperature, and voltage. A summary of these driving forces that induce Mott-transition is presented together with their specific transition mechanisms for different materials. This is followed by a dynamics study of oxygen vacancy migration in voltage-driven non-volatile Mott-transition and the related resistive switching performance. We distinguish between a filling-controlled Mott-transition, which corresponds to the conventional valence change memory effect in band-insulators, and a bandwidth-controlled Mott-transition, which is due to a change in the bandwidth in the Mott system. Last, different types of Mott-RRAM-based neural network concepts are also discussed. The results in this review provide guidelines for the understanding, and further study and design of Mott-transition-based RRAM materials and their correlated devices.