Lateral alloy segregation in thin heteroepitaxial films

Alloy segregation is believed to be an important factor in the growth of the wetting layer and subsequent formation of islands during heteroepitaxy. We report simulated annealing results that determine the lowest-energy configuration of a strained system. Our results indicate that in addition to vertical segregation, there is also an energetic driving force for lateral segregation and formation of subsurface features before island formation. We believe that these subsurface features play a crucial role in the nucleation of islands.