SURFACE SELF-DIFFUSION AT HIGH-TEMPERATURES - NEW SIMULATIONAL INSIGHTS

Surface self diffusion has been simulated using both Lennard-Jones and Stillinger-Weber potentials in order to explain why experimental acti vation energies and pre-exponential factors increase greatly at large fractions of the substrate melting point. With both potentials, these effects are observed clearly in simulations and are caused by the prol iferation of adatom-vacancy pairs at these temperatures. At the very h ighest temperatures near melting, the activation energy and prefactor decrease again as the diffusion becomes liquid like.