Dislocation Mechanism for Island Diffusion on fcc (111) Surfaces

We describe a novel mechanism for diffusion of homoepitaxial 2D islands on fcc (111) surfaces by nucleation and motion of misfit dislocations. Embedded atom method molecular dynamics calculations show that this mechanism will compare favorably with edge running and simultaneous gliding for islands up to some tens of atoms in size. We suggest that this mechanism may facilitate diffusion of heteroexpitaxial strained overlayer islands containing dislocations in their lowest energy configurations.