Electromigration of small vacancy clusters on the (100) copper surface

The electromigration of small vacancy islands on the Cu(100) surface has been studied using the self-learning kinetic Monte Carlo method. The dependence of the drift velocity of vacancy clusters on their size, temperature of the substrate, and magnitude and direction of the electric current density has been obtained. It has been shown that the dependence of the drift velocity of small clusters on their size has a pronounced oscillatory character. These oscillations are due to the difference in the mechanisms of diffusion of “fast” and “slow” clusters. It has been found that events associated with the diffusion of dimers should be taken into account for the correct simulation of the electromigration of vacancy clusters.