The Stillinger-Weber potential was used to model the migration of a Si atom which was adsorbed at a 2 x 1 (100) surface. The adsorption sites and the barriers between them were determined by means of energy minimization methods, and were used to estimate the rate of site-to-site hopping. A stochastic kinetic simulation which used these rates determined how the adsorbed atom migrated on the surface. It was found that the mobility was highly anisotropic, and that the motion was quasi one-dimensional. The particle diffused along the dimer row and then became trapped on sites which were located between the dimers. The activation energy for diffusion was a complicated function of the energy barriers which separated the surface sites. The pre-exponential factor could have unusual values.

Y.T.Lu, Z.Zhang, H.Metiu: Surface Science, 1991, 257[1-3], 199-209