EXCHANGE MECHANISMS FOR SELF-DIFFUSION ON ALUMINUM SURFACES

We present the results of molecular dynamics simulations and energy mi nimisation calculations for the diffusion of an Al adatom on Al(110) a nd Al(100) surfaces using a realistic many-body potential. For the Al/ Al(110) system, the adatom motion is found to involve both a simple at omic-hopping mechanism, for displacements along the surface channels, and an atomic-exchange mechanism for displacements across the channels . On the (100) surface diffusion proceeds by an exchange mechanism. Th e transition state for this process is stabilised by strong covalent b onding.