Instabilities that were caused by Schwoebel barriers during growth, and their effects upon growth or sublimation by step flows, were investigated by using the Stillinger-Weber potential; especially with regard to how this step-edge barrier arose in the case of the 2 high-symmetry steps on 1 x 1 reconstructed (111). Relative to a barrier of 0.97eV on the surface, additional (Schwoebel) barriers of 0.61 and 0.16eV were found for adatom migration over the [2¯11] and [1¯1¯2] steps, respectively. The adatom potential energy was found to be strongly related to that which was derived from the local geometry of atoms on the adatom-free surface or step edges. This correlation preserved a strict correspondence between the barrier-determining features of the spatial variation of the adatom potential energy, and the same value as derived from the local geometry of the Si(111) surface and the [2¯11] step. It was suggested that the Schwoebel barrier on the [2¯11] step was a feature that would appear in more searching  ab initio  or tight-binding calculations. By using a diffusion equation for the adatom concentration, the relevance of the barrier to the electromigration of steps was analyzed. Experimental data on (111) were used to place an upper bound on the Schwoebel barrier, and a lower bound on the electromigration force.

S.Kodiyalam, K.E.Khor, S.Das Sarma: Physical Review B, 1996, 53[15], 9913-22