The migration of 2-dimensional Pb clusters on the (111) Cu surface was studied in the framework of a 3-dimensional continuum space tight-binding computational model. Monte Carlo simulations based upon many-body tight-binding interactions revealed a significant influence of cluster-substrate misfit upon the diffusion behavior of 2-dimensional clusters. An analysis of the pair distribution function demonstrated that the cluster lattice constant depended upon the number of atoms, N, for 1 < N < 10. The observed effect was more pronounced for hetero-epitaxial than for homo-epitaxial systems. It could be explained within the framework of a model which accounted for enhanced charge transfer in hetero-epitaxy and a strong influence of surface potential upon the cluster atomic arrangement. The variation in the lattice constant led to a variable misfit which affected the island migration behavior. The results were analysed using a physical model that implied the occurrence of cluster diffusion with a size-dependent cluster/substrate misfit.

Surface Diffusion of Pb Clusters on Cu(111) Influenced by Size Dependent Cluster-Substrate Misfit - Monte Carlo Tight Binding Simulation Model. M.Michailov, M.Vladkov: Surface Science, 2007, 601[18], 3912-5

Table 3

Grain-Boundary Diffusion of Ni in Cu