THEORETICAL-STUDIES OF ADATOM DIFFUSION ON METAL-SURFACES

We propose in this paper a theoretical model to investigate surface se lf-diffusion of single adatoms on two different low-index planes, clos ely packed (001) and densely packed (111), of face-centered-cubic rhod ium, nickel and copper metal crystals. Two realistic model potentials are applied to describe the interatomic interaction of the adatom-subs trate systems. The first model is a Morse-type potential, which involv es several empirical fittings of bulk properties of solid. The second, newly popular, potential was introduced by Sutton and Chen, which inc orporates many-body effects. With these potentials, conventional molec ular dynamics (MD) is employed to obtain trajectories of the atoms. Th e average squared displacements are computed for a range of initial ki netic energies, and the surface diffusion constants can be obtained by means of the Einstein relation. The estimated random walk exponential prefactors and activation energies exhibit an Arrhenius behavior, and are compared with previous results.