First-principles calculations, using the full-potential linear muffin-tin orbital technique, were used to determine the energy barriers to adatom homo-diffusion on the (100) and (111) surfaces. It was found that the results agreed with measured energy barriers (where known) to within 0.03eV. In the case of (111) surfaces, the barriers for Ag and Ir had values that were close to those which corresponded to the melting point of the bulk material. It was deduced that so-called correlated jumps occurred at high temperatures on these surfaces. In the case of (111)Au, the barrier was about twice as large as that at the melting point, and the random-walk model was expected to provide an accurate description of the diffusion process; as in the case of (100) surfaces (where the barriers were much higher). Semi-empirical models reproduced the first-principles energy barriers to within 0.2eV (giving errors of up to 90%).

G.Boisvert, L.J.Lewis, M.J.Puska, R.M.Nieminen: Physical Review B, 1995, 52[12], 9078-85