First-principles total-energy calculations were presented which revealed the microscopic structures of steps, and the mechanisms of adatom diffusion, on hydrogenated (100) surfaces. The energetics of several types of step depended upon the H chemical. potential. The non-rebonded structure was more stable than the rebonded, for a wide range of chemical potentials. Calculations of the diffusion pathways, and activation barriers to adatoms, showed that the Schwoebel barrier was absent near to the single-layer steps. It was also found that a non-rebonded step was a deep sink for the adatom during epitaxial growth.

Structural Stability and Adatom Diffusion at Steps on Hydrogenated Si(100) Surfaces S.Jeong, A.Oshiyama: Physical Review Letters, 1998, 81[24], 5366-9