Cluster on the fcc(111) surface: structure, stability and diffusion

The static and dynamical properties of a highly symmetric cluster on a fcc(111) surface are studied using the molecular-dynamics method. We find that the cluster can only be stable on the surface up to a certain temperature much lower than the melting temperature of the corresponding isolated cluster; the surface can strongly change the thermal properties of the cluster. The fast diffusion of the cluster is attributed to the rolling of cluster as a whole on the surface, and the dependence of diffusion constants on the structural mismatch is also studied.