First-Principles Investigation of the Resistive Switching Mechanism in Monolayer MoS₂—Insights into Metal Diffusion and Adsorption

A deeper understanding of memristive switching in two dimensional (2D) materials holds significant promise for advancing neuromorphic computing. The Dissociation Diffusion Adsorption (DDA) model provides a valuable framework for exploring the underlying mechanisms governing resistive switching (RS) in memristive systems. This study leverages first-principles density functional theory (DFT) to investigate the phenomena of dissociation, diffusion, and adsorption within the DDA model, focusing on metal atoms (Au, Ag, Cu) interacting with monolayer MoS₂. We analyzed the diffusion energy barriers for metal atoms on pristine and sulfur-vacancy MoS₂ structures using nudged elastic band (NEB) calculations. The influence of electrostatic potential on the energy barriers was explored under both positive and negative charged systems for minimum energy pathways. Additionally, the dissociation and adsorption of metal atoms in heterostructures (metal/MoS₂) were simulated. Our findings reveal that Ag/MoS₂ exhibits the lowest energy barrier for dissociation and adsorption, while Au and Cu have comparably higher barriers ~0.38eV. Bader charge analysis provides insights into the behavior of metal atoms as they interact with sulfur vacancies and adopt a negative charge. This study offers a comprehensive understanding of the DDA mechanism for RS in 2D MoS₂ and provides valuable guidance for optimizing switching energy and device performance. Future investigations can extend these studies to other 2D materials and metal atoms to further explore the underlying principles of switching in memristors, with a particular focus on their potential applications in neuromorphic circuits.