Influence of the 2D periodic potential shape on the jump diffusion in the strong collision limit

Abstract

In this paper, the dynamic properties of a single adatom subject to a two-dimensional periodic potential of square symmetry are investigated. This problem is addressed through the strong-collision model, where the dynamical interaction of the adatom with the substrate is modeled by well-separated collisions that thermalize the velocity. By means of molecular dynamics simulations, we calculate the jump-length probability distribution and the diffusion coefficient as a function of x–y coupling term and of the collision frequency [Formula: see text]. Our numerical results show that the x–y coupling always suppresses a large proportion of long jumps, inducing thus a decrease of the diffusion coefficient for all values of [Formula: see text]. Implications of these findings are briefly discussed.