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.
Zoethout, E., Gurlu, O., Zandvliet, H. J. W., & Poelsema, B. (2000). The influence of strain on the diffusion of Si dimers on Si(001). Surface science, 452(1-3), 247-252. https://doi.org/10.1016/S0039-6028(00)00338-1