The diffusion of a surface vacancy on Cu(111) was studied by means of molecular dynamics in conjunction with the many-body potential derived from the second-moment approximation of the tight-binding model. The calculations performed in the high-temperature range revealed that the surface vacancy diffusion occurred mainly via random nearest-neighbour hops with the activation energy close to the static migration barrier. Small contributions of the third-neighbour surface-layer jumps and jumps between the first and the second layer were also recorded. The latter jumps were likely to be possible due to some dynamical co-operative effect among neighbouring atoms around a vacancy that effectively reduced the inter-layer migration barrier.

Surface Vacancy Diffusion on Cu(111): a Computer Simulation Study. Mikhin, A.G., de Diego N.: Surface Science, 1998, 418[1], 166-70