Irreversible Nucleation in Molecular Beam Epitaxy: From Theory to Experiments

Recently, the nucleation rate on top of a terrace during the irreversible growth of a crystal surface by molecular-beam epitaxy has been determined exactly. In this paper we go beyond the standard model usually employed to study the nucleation process, and we analyze the qualitative and quantitative consequences of two important additional physical ingredients: the nonuniformity of the Ehrlich-Schwoebel barrier at the step edge, because of the existence of kinks, and the steering effects, due to the interaction between the atoms of the flux and the substrate. We apply our results to typical experiments of second-layer nucleation.