Geometrical, electronic, and magnetic properties of small Au nSc ( n=1–8) clusters

Abstract

Geometrical, electronic, and magnetic properties of the Sc-doped gold clusters, Au n Sc ( n=1–8), have been studied using the density-functional theory within the generalized gradient approximation. An extensive structural search shows that the Sc atom in low-energy Au n Sc isomers tends to occupy the most highly coordinated position. The substitution of a Sc atom for an Au atom in the Au n+1 cluster markedly changes the structure of the host cluster. Moreover, we confirm that the ground-state Au 6Sc cluster has a distortion to a lower D 2h symmetry. The relative stabilities and electronic properties of the lowest-energy Au n Sc clusters are analyzed based on the averaged binding energies, second-order energy differences, fragmentation energies, chemical hardnesses, and HOMO–LUMO gaps. It is found that the magic Au 3Sc cluster can be perceived as a superatom with high chemical stability and its HOMO–LUMO gap is larger than that of the closed-shell Zr@Au 14 cluster. The high symmetry and spin multiplicity of the Au 3Sc and Au 6Sc clusters are responsible for their large vertical ionization potential and electron affinity. The magnetism calculations indicate that the magnetic moment of the Sc atom in the ground-state Au n Sc ( n=2–8) clusters gradually decreases for even n and is completely quenched for odd n.