The diffusion of adsorbed Si dimers on the reconstructed Si(001) surface was studied using molecular dynamics and an environment-dependent tight binding potential. Simulations were performed at 1300K; 163K below the experimental temperature at which the p(2x1) surface reconstruction was lost. Different initial conditions were considered in each of 64 simulations, giving a total simulation time of 5748ps. At this temperature, Si ad-dimers were still able to diffuse as a unit, without dissociation. Three different pathways were found for diffusion between the top of the dimer rows and the trough. One of them had already been predicted by low-temperature studies and the other two were activated at high temperature and made the diffusion less anisotropic.

Finite Temperature Simulation of Ad-Dimer Diffusion between Dimer Row and Trough on Si(001). Fu, C.C., Weissmann, M., Saúl, A.: Applied Surface Science, 2001, 175-176, 36-42