Diffusion of atoms incorporated in the surface layer of the fcc(111) face

The kinetics of the migration of the impurity atom due to the diffusion of vacancies on the fcc(111) face was investigated. The study focused on the dependence of the diffusion coefficient of the impurity on the degree of surface coverage with vacancies. It was shown by molecular dynamics that this dependence is linear in the limit of the vanishingly small concentration of vacancies 1; the results of modeling coincided with the predictions of our analytical theory. The diffusion coefficient increased nonlinearly with and its growth correlated with that of the size of the percolation clusters. After the percolation threshold was overcome, the diffusion coefficient of the impurity quickly tended toward its value for the surface without hindrances.