Geometries, stabilities, and electronic properties of YnSi (n = 2–14) clusters: Density-functional theory investigations

Using the density-functional approach, the geometries, stabilities, electronic properties, and magnetism of the YnSi (n = 2–14) clusters have been systematically investigated. The growth pattern for the different-sized YnSi (n = 2–14) clusters is Si-substituting Yn+1 clusters and keeps the similar frameworks of the most stable Yn+1 clusters. The Si atom substitutes the surface atom of the Yn+1 clusters for n < 8. Starting from n = 8, the Si atom completely falls into the center of the Y-frame. The Si atom substitutes the center atom of the Yn+1 clusters to form the Si-encapsulated Yn geometries for n > 8. The calculated results show that doping of Si atom contributes to strengthening the stabilities of the yttrium framework. In addition, the relative stability of Y12Si is the strongest among the investigated YnSi clusters, which might stem from its highest symmetry. Mulliken population analysis shows that charges always transfer from Y atoms to Si atom in all the YnSi (n = 2–14) clusters. Doping of Si atom decreases the magnetic moments of the most Yn clusters. In particular, the magnetic moment does quench completely after doping Si in Y13, which is ascribed to the disappearance of the itinerant 4d electron spin exchange effect. Finally, the frontier orbitals properties of YnSi are also discussed.