In order to show how experimental observations of equilibrium step fluctuations could be used to explore the mechanisms of surface mass self-diffusion, a study was made of the equilibrium fluctuations of vicinal surfaces. This involved the use of a solid-on-solid Monte Carlo kinetic model, with no special barriers to attachment at step edges. By examining the wavelength dependence of the time constants of the fluctuations, it was found that the step fluctuations were governed by the rate at which adatoms and vacancies could diffuse away from step edges. This result was compared with the case where step-edge attachment became the rate-limiting process. The results in the former case were used to comprehend how steps diffused when their configuration was out of equilibrium. In particular, calculations were made of how steps broke apart (due to entropic repulsion) to form a uniform step array. It was shown that the surface mass diffusion coefficient which was deduced by analyzing step fluctuations could account for the evolution of the step bunch.

N.C.Bartelt, T.L.Einstein, E.D.Williams: Surface Science, 1994, 312[3], 411-21