Step Motion on Crystal Surfaces. II

A theory for step motion on crystal surfaces undergoing growth, evaporation, and annealing is described. The capture and detachment of atoms at surface steps is considered to occur with arbitrary probability. It is shown that differences in the capture and/or detachment probabilities lead to important characteristics of the step motion. Surfaces with sinusoidally distributed steps will smooth or roughen during growth or evaporation in the same manner as predicted by macroscopic capillarity theory. The conditions under which the kinetic and quasiequilibrium considerations apply are given in terms of the capture and detachment rate constants.