Structures, Stabilities, and Electronic Properties of Gold Silicide Clusters: Comparison with Pure Silicon Clusters

Abstract

The local meta-GGA (generalized gradient approximation) exchange correlation density functional (TPSS) with relativistic effective core potential was employed to systematically investigate the geometric structures, stabilities, and electronic properties of bimetallic Au 2 Si n (n = 1 -8) clusters. The optimized geometries show that the most stable isomers have a three-dimensional structure except for Au 2 Si 1,3 clusters. The doped gold atoms prefer to occupy the surface site in the Au 2 Si n clusters. Here, the averaged atomic binding energies and fragmentation energies show that the Au 2 Si 5 isomer is the most stable among the Au 2 Si n (n = 1 -8) clusters. A pronounced even-odd alternation is found in the energy difference between the highest occupied and the lowest unoccupied molecular orbital (HOMO-LUMO gaps), especially, the Au 2 Si 5 cluster has the largest HOMO-LUMO gap of 2.06 eV. Moreover, the reverse even-odd alternation rule to the average polarizability per atom versus the charges transfer was found. A transition point appears at n = 5.

Evidence of chromium-cobalt binary cluster formation by pulsed laser evaporation

“…Theoretical and experimental cluster studies have also been made on more complex materials, including II-VI semiconductors 11 , silicides 12,13 and some copper 14 and aluminum compounds 15,16 , among others. Intermediate between the mixed covalentionic bonding of II-VI materials, and the purely metallic bonding of noble metal clusters lies an interesting regime where the formation of intermetallic compounds is observed in the bulk phase diagram.…”