Global Minimum Structures and Magic Clusters of CumAgn Nanoalloys

The putative global minimum structures of bimetallic CumAgn nanoalloys for all (m,n) with N = m + n from 2 to 60 atoms have been determined. The embedded-atom method was used for the description of the interatomic interactions in combination with the basin-hopping algorithm for the global structural optimization. The obtained global-minimum structures are mostly based on icosahedra, polyicosahedra as well as 5-fold pancakes. But also truncated octahedral are found for some clusters with 38 atoms. The bond-order parameter reveals the formation of CucoreAgshell clusters. The analysis of energetic properties, through stability functions, the excess and the mixing energies, gives that the clusters with more Ag atoms are energetically more favorable. Moreover, from our analysis we identify the most stable stoichiometries as a function of N. Finally, the results of the present study are compared with similar results on NimAgn clusters.