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 AgnSi (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 sp3 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 Ag4Si structure is the most stable geometry for the AgnSi 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 Ag4Si and Ag5, which illustrates that the corresponding Ag4Si cluster has dramatically enhanced chemical stability.