Epitaxy for Weakly Interacting Systems of Large Misfit

Abstract

ABSTRACTA simple but general model is developed which describes the elastic relaxations in a misfitting epitaxial thin film on a rigid substrate. The film is treated as a two-dimensional, elastically anisotropic solid with an arbitrary orientation relationship to the underlying substrate. The periodic elastic displacement field, the misfit energy density, and the elastic energy density of relaxation are derived for relatively weak, periodic film-substrate interactions of a generalized form. The model is tested for a misfitting Ni-(111) monolayer in contact with a rigid Ag-(111) substrate, using computer simulations with the embedded atom method. The predicted displacement field has symmetry 3m and has a magnitude which is in close agreement with that obtained by a fully numerical solution. The dependence of the extent of relaxations on the form of the film-substrate interaction is discussed for the special case of unidirectional misfit.