First-principles study on the geometries, stabilities and electronic properties of yttrium-silicon clusters (Y2Si (n); 1 a parts per thousand currency sign n a parts per thousand currency sign 12)

摘要

The geometries, growth patterns, relative stabilities and electronic properties of yttrium-doped silicon clusters Y2Si (n) (n = 1-12) are systematically investigated using the density functional theory at B3LYP/GENECP level. The optimized structures show that most of the lowest energy Y2Si (n) structures keep the corresponding Si (n+2) framework unchanged. The stabilities analysis reveals that the Y2Si3, Y2Si9 and Y2Si11 clusters have relatively higher stabilities than other clusters, and the doping of Y atoms reduces the chemical stabilities of Si (n+2) clusters. The natural population and natural electronic configuration analysis indicate that the charges in the corresponding Y2Si (n) clusters always transfer from Y atoms to Si atoms and there exists the spd hybridization in the Y atom. The Y2Si9 cluster has the largest chemical hardness and smallest chemical potential. Atom-in-molecules analysis indicates that the chemical bonding between Si and Y atoms has an ionic character.