Electromigration-induced flow of islands and voids on the Cu(001) surface

Electromigration-induced flow of islands and voids on the Cu(001) surface i s studied at the atomic scale. The basic drift mechanisms are identified us ing a complete set of energy barriers for adatom hopping on the Cu(001) sur face, combined with kinetic Monte Carlo simulations. The energy barriers ar e calculated by the embedded atom method, and parametrized using a simple m odel. The dependence of the flow on the temperature, the size of the cluste rs, and the strength of the applied field is obtained. For both islands and voids it is found that edge diffusion is the dominant mass-transport mecha nism. The rate Limiting steps are identified. For both islands and voids th ey involve detachment of atoms from corners into the adjacent edge. The ene rgy barriers for these moves are found to be in good agreement with the act ivation energy for island and void drift obtained from Arrhenius analysis o f the simulation results. The relevance of the results to other fcc(001) me tal surfaces and their experimental implications are discussed.