Transitions in critical size in metal (100) and metal (111) homoepitaxy

Transitions in the critical island size i in submonolayer growth from i = 1 to i = 2 and From i = 1 to i = 3, corresponding to homoepitaxial growth on metal (111) and (100) surfaces. are studied using kinetic Monte Carlo simulations of a restricted pair-bond model, both with and without island relaxation. and are compared with rate-equation predictions. In both cases, the rate equations significantly underestimate the transition temperature from i = 1 behavior to a higher critical island size. The difference is due to the neglect of spatial correlations in the standard rate-equation approach. A partial solution involving the use of effective detachment rates is proposed. (C) 1997 Elsevier Science B.V.