Spinodal decomposition in a film with periodically distributed interfacial dislocations

Phase field approach is applied to modeling the spinodal decomposition process in a thin film with periodically distributed arrays of interfacial dislocations. The elastic stress field in the simultaneous presence of interfacial dislocations, substrate constraint, and compositional strains is obtained by solving the mechanical equilibrium equations using an iteration method. It is shown that the periodic stress field associated with the array of interfacial dislocations leads to a directional phase separation and the formation of ordered mesoscale microstructures. It is demonstrated that when the periodicity of the dislocation is small, the wavelength of the ordered microstructure tends to be the same periodicity as the dislocation array. The results have important practical implications that an ordered nanostructures could be produced by controlling the interfacial dislocation distribution.