Comparative study of Cu13 and Co13 clusters deposition and diffusion on the Cu(001) surface

The soft deposition of Cu-13 and Con clusters and their subsequent diffusion behaviors on the Cu(0 0 1) surface have been studied via molecular dynamics simulations with many-body potential based on the tight-binding model. Terrace-step-kink structures are used for the description of the substrate geometries. The results show that the final morphologies and the binding energies of the deposited clusters depend sensitively on the substrate surface geometries. The diffusion behaviors of the clusters on the substrate are investigated via annealing the cluster-substrate systems at 300 K, 500 K and 800 K. It is shown that the significantly different diffusion behaviors of Cu-13 and Coo clusters are associated with different interactions between Cu-Cu, Co-Co, and Cu-Co atoms. Our results also reveal that the Cu-13 and Co-13 clusters collapse on the terrace at 800 K via the solid-on-solid settling mechanism. A new collapse mechanism is also discovered during the collapse process of Coo cluster, which suspends the transformation from a three-dimensional adsorbed cluster to a two-dimensional one. (c) 2010 Elsevier B.V. All rights reserved.