Embedded atom method potentials were used to calculate the Schwoebel barriers for a large number of hopping and exchange processes of Pt and Ni adatoms descending steps on a Pt(111) surface. The barriers which were found for hopping processes were too high to play any role in homo- or hetero-epitaxy, but very low (or even negative) Schwoebel barriers were found for exchange processes at concave corners and kinks. It was found that, on straight steps, the process took place on B-steps rather than on A-steps; with very similar Schwoebel barriers for Ni and Pt adatoms. A strong dependence of the Schwoebel barrier upon the lateral relaxation of step edges, as caused by surface stresses, was also found. For vicinal surfaces with a high step density, this caused an increase in the Schwoebel barrier when the width of the (111) terraces was reduced. Due to this same effect, the barriers were expected to be different for the small cell-sizes of the present ab initio calculations, as compared with larger terraces.

Adatom Interlayer Diffusion on Pt (111) - an Embedded Atom Method Study. G.Leonardelli, E.Lundgren, M.Schmid: Surface Science, 2001, 490[1-2], 29-42