The diffusion of a single Pt adatom on the Pt(111) surface with {111}-faceted steps was studied using a combination of molecular dynamics and the nudged elastic band method. The interatomic interactions were described with the analytic embedded atom method. The simulation indicates that before diffusion across the descending step, the adatom becomes trapped at the step edge, and has to overcome an energy barrier to return the plane's center. The energy barrier for adatom migration to the step edge was almost independent of step thickness. In addition, the step thickness dependence of the diffusion energy barrier for the adatom over descending and ascending steps edge was obtained. For a monolayer step, the upward diffusion of the adatom to the {111}-faceted steps was very rare as compared with the downward diffusion. However, the probability of the adatom to ascend the {111}-faceted steps increases with increasing step thickness. The calculated character temperatures indicate the three-dimensional pyramidal island on the clean Pt(111) surface could be formed at higher temperature.

The Effect of Step Thickness on the Surface Diffusion of a Pt Adatom. J.Yang, W.Hu, S.Chen, Y.Deng, G.Xiao: Modelling and Simulation in Materials Science and Engineering, 2009, 17[7], 075004