Resistive Switching Driven by Electric Field in the Mott Insulators AM4X8 (A = Ga, Ge; M= V, Nb, Ta; X = S, Se): Towards a New Class of Non-Volatile RRAM Memory

We report here on a new type of non volatile resistive switching that we discovered in the whole class of Mott Insulator compounds AM₄X₈ (A = Ga, Ge; M= V, Nb, Ta; X = S, Se). The mechanism of this resistive switching differs from the thermochemical or electrochemical effects reported so far to explain the resistive switching in other materials. We found that this resistive switching is related to an electric field effect which induces an electronic phase change in the AM4X8 compounds from the Mott insulating state to a metallic-like state. This new type of resistive switching is observed both on crystals and on polycrystalline thin films with fast writing/erasing times (50 ns to 10 μs) and resistance ratios (ΔR/R_low) higher than 33% at room temperature. These results appear very promising at developing a new class of Resistive Random Access Memory (RRAM).