Structure and electronic properties of cobalt atoms encapsulated in Sin (n = 1-13) clusters

A systematic theoretical study of the equilibrium geometries and energetics of cobalt atoms encapsulated in Sin (n = 1-13) clusters and comparison with pure Sin clusters have been performed by density functional theory-generalized gradient approximation calculations combined with a genetic algorithm. Our results reveal that the geometries of bare Sin clusters are substantially modified upon doping of Co atom. Co-doping improves the stability of the clusters after n ⩾ 7. In general, the stability of SinCo clusters increases with increasing size n. The Si9Co was found as magic-number cluster, and the enhanced stability was explained by the 18-electron rule. The magnetic moment on Co atom inside SinCo cluster is quenched in all the clusters with n ⩾ 4.