A Systematic Search for Structures, Stabilities, Electronic and Magnetic Properties of Silicon Doped Silver Clusters: Comparison with Pure Silver Clusters

Abstract

The geometric structures, stabilities, electronic and magnetic properties of silicon doped silver clusters Ag n Si (n = 1 -9) have been systematically investigated by using meta-generalized gradient approximation (meta-GGA) exchange correlation Tao-Perdew-Staroverov-Scuseria (TPSS) functional. Due to the sp 3 hybridization, the lowest energy structures of doped clusters favour the threedimensional structure. The silicon atom prefers to be located at the surface of the host silver clusters. The isomers that correspond to high coordination numbers of the Si-Ag bonds are found to be more stable. By analyzing the relative stabilities, the results show that the quadrangular bipyramid Ag 4 Si structure is the most stable geometry for the Ag n Si clusters. Meanwhile, the fragmentation energies, second-order difference of energies, difference of highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO gaps), and total magnetic moments exhibit pronounced even-odd alternations. The largest hardness difference (2.24 eV) exists between the clusters Ag 4 Si and Ag 5 , which illustrates that the corresponding Ag 4 Si cluster has dramatically enhanced chemical stability.