First-Principles Investigation of Defect- and Interface-Controlled Resistive Switching in 2D Transition Metal Dichalcogenides

Non-volatile resistive switching (NVRS) in two-dimensional (2D) transition-metal dichalcogenides (TMDs) offers a platform to explore field-driven electronic and structural transformations at the atomic scale. Despite increasing experimental reports of switching in TMD-based heterostructures, the microscopic origin of the process remains debated, often attributed solely to filament formation or adatom migration. Using first-principles density-functional theory (DFT) and nonequilibrium Green’s function (NEGF) transport simulations, we investigate a multistage switching mechanism governed by both monatomic defect complexes and interfacial coupling between metallic electrodes and TMD layers. Electric-field-induced motion of the central TMD layer modulates interlayer spacing and interfacial charge transfer, significantly influencing conductivity. In conjunction, adsorption of single Au atoms at S-vacancy sites introduces localized electronic states that strongly alter transmission pathways. These results highlight the interplay between defect energetics, field-driven atomic displacements, and interfacial bonding in determining resistive states. Ongoing work extends this analysis to additional electrodes to identify general descriptors for defect-mediated switching in 2D materials.