Time correlations and statistics of atomistic processes in island diffusion on fcc(1 0 0) metal surfaces

The diffusion of 2D adatom islands on fcc(1 0 0) metal surfaces has recently been studied with large-scale Monte Carlo simulations of a lattice-gas model, with energetics based on effective medium theory calculations. It has been shown that in the limit of large islands the diffusive motion crosses over from periphery dominated mechanism to a regime where vacancies diffuse inside the island. Here we consider the role and statistics of various atomistic processes for diffusion of islands of various sizes. This analysis reveals the nature of the crossover behavior in terms of the underlying microscopic processes. We also study the memory effects by examining the temporal behavior of the velocity autocorrelation function. It reveals that there are no anomalities in the long-time correlations of the microscopic processes.