Atomistic description of conductive bridge formation in two-dimensional material based memristor

In-memory computing technology built on 2D material-based nonvolatile resistive switches (aka memristors) has made great progress in recent years. It has however been debated whether such remarkable resistive switching is an inherent property of the 2D materials or if the metal electrode plays any role? Can the metal atoms penetrate through the crystalline 2D materials to form conductive filaments as observed in amorphous oxide-based memristors? To find answers, here we investigate MoS2 and h-BN-based devices with electrochemically passive and active (metal) electrodes using reactive molecular dynamics with a charge equilibration approach. We find that the SET and RESET processes in active electrode-based multilayer devices involve the formation and disruption of metal filaments linking the two electrodes exclusively through the grain boundaries, the configuration of which affects the volatility of the resistive switching. Whereas the switching mechanisms in passive electrode-based devices require the formation of interlayer B-N bonds and popping of the S atom to the Mo plane at the point defects. We also show that metal atom adsorption at the point defects causes resistive switching in monolayer MoS2. Our atomic-level understanding provides explanations to the apparently contradictory experimental findings and enables defect-engineering guidelines in 2D materials for such disruptive technology.