Influence of strain on the diffusion of Si dimers on Si(001)

The influence of lattice mismatch-induced tensile strain on the diffusion of Si dimers on Si(001) has been studied. The rate of surface diffusion of a Si dimer along the substrate dimer rows is relatively insensitive to tensile strain, whereas the rate of diffusion for a Si dimer across the substrate dimer rows is significantly enhanced. The insensitivity of the along row diffusion rate for tensile strain is attributed to the presence of a dissociative intermediate state of the ad-dimer during diffusion rather than diffusion as a solid unit.