First-Principles Study of Superlubricity of Two-Dimensional Graphene/ WS₂ Heterostructures

Layered two-dimensional nanomaterials such as graphene and WS₂, possess superlubricity properties and thus offer a promising solution to mitigate friction and wear in micro-electromechanical systems. In this study, the atomic friction properties of graphene/graphene, WS₂/WS₂, and graphene/WS₂ bilayer heterostructure systems were examined through density functional theory simulations. Results indicated that the friction strength of the graphene/WS₂ bilayer heterostructure system was lower than that of the graphene/graphene and WS₂/WS₂ systems. Specifically, the graphene/WS₂ bilayer heterostructure system demonstrated ultra-low friction coefficients ranging from 0.0006 to 0.0096, resulting in friction strengths in the range of 10^⁻³ nN. Furthermore, the heightened electrostatic repulsion and smooth potential energy fluctuation helped reduce friction, validating the superlubricity performance of the graphene/WS₂ heterostructure system.