Theory of surface electromigration on heterogeneous metal surfaces

We report a calculation of the magnitude of the wind force for the self-electromigration of adatoms on heterogeneous metal surfaces. Using a layer-KKR method we computed the wind valence of adatoms within small monolayer islands and voids on Cu(1 0 0). We show that the electromigration driving force felt by an adatom is significantly altered by the scattering of carriers among neighboring atoms within the island. Using the results of these calculations as input to kinetic Monte-Carlo simulations, we explore how this inhomogeneity of the wind force is manifest in the driven surface diffusion of Cu islands on a current-carrying Cu(1 0 0) substrate.