Surface smoothing during sputtering: mobile vacancies versus adatom detachment and diffusion

Surface smoothing during sputtering can occur through both vacancy diffusion and adatom diffusion. In this paper, using kinetic Monte Carlo simulations, we investigate the kinetic consequences of smoothing with either mechanism acting alone. Quasi-layer-by-layer sputtering and an approximately Arrhenius variation of pit density during submonolayer sputtering are observed with both types of surface smoothing. However, the two mechanisms result in significant differences in the pit size distribution for submonolayer sputtering and the vacancy coverage at which the maxima of the anti-Bragg specular beam intensity oscillations occur during layer-by-layer sputtering. These and other experimentally observable quantities are investigated as possible ways to determine the relative importance of the two smoothing mechanisms.