It was noted that an atomic step on a solid surface could act not only as a reflective or non-reflective boundary, but also as an atom-trapping boundary. By using field ion microscopy, the behavior of adatoms at, and near to, steps on (001) and (111) surfaces was monitored in detail. Activation barrier heights for various atomic processes at step boundaries, and the atom-trapping strengths of step-edge sites, were measured. It was found that the above surfaces exhibited entirely different step properties. At the terraces, near to steps on (111), an empty zone of adatom occupation was found whose width depended upon the terrace size. There was also a difference in the reflective barrier heights of the A-type and B-type step-edges of (111) layers.

Energetics of Surface Atomic Processes near a Lattice Step T.Y.Fu, H.T.Wu, T.T.Tsong: Physical Review B, 1998, 58[4], 2340-6