The binding sites and diffusion barriers for a Si adatom moving on a buckled (100) surface with single-height steps were calculated by using  ab initio  methods. It was found that the diffusion barriers could be sensitive to local buckling of the dimers, and that the adatom binding energies and escape barriers at step edges depended strongly upon the type of step. The SA step edge was a relatively poor sink for adatoms, while adatoms could be easily trapped at the SB edges. It was concluded that these results explained the fast growth which was observed at the ends of the dimer rows.

Q.M.Zhang, C.Roland, P.Boguslawski, J.Bernholc: Physical Review Letters, 1995, 75[1], 101-4