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 M onte Carlo simulations of a restricted pair-bond model, both with and without island relaxation. and are compared with rate-equation predict ions. In both cases, the rate equations significantly underestimate th e transition temperature from i = 1 behavior to a higher critical isla nd size. The difference is due to the neglect of spatial correlations in the standard rate-equation approach. A partial solution involving t he use of effective detachment rates is proposed. (C) 1997 Elsevier Sc ience B.V.