The superlubricity of the special material with hexagonal symmetry in a two-dimensional Frenkel–Kontorova model

Abstract

Based on a two-dimensional Frenkel–Kontorova model, the interacting atoms arranged on a two-dimensional hexagonal lattice are studied. It is made to slide by the application of an external driving force in the presence of dissipation over a two-dimensional periodic substrate potential with the hexagonal symmetry. A critical depinning force is defined. It depends on the direction and the magnitude of external driving force, the adhesive force from the substrate, the interaction strength between atoms in the upper layer and especially the misfit angle $$\theta $$ between two layers. The dependence of the state transition from the lock to sliding on the driving force is studied. For the special case of zero misfit angle, the analytical expressions for the critical depinning force are obtained which are in a good agreement with numerical ones. It seems that the superlubricity can appear.