Structure, stability, and magnetism of ScnAl (n=1-8,12) clusters: Density-functional theory investigations

Equilibrium geometries and electronic and magnetic properties of small ScnAl (n=1-8,12) clusters have been studied based on the density-functional theory with all-electron spin-polarized generalized gradient approximation. The calculated results show that the Al atom remains on the surface for n=1-8, but at the center of the Sc12Al cluster with a variable icosahedral structure (C-3 nu). Doping of the Al atom enhances the stability of the scandium clusters. Maximum peaks are observed for clusters of n=3,6 on the size dependence of the second-order energy differences and fragmentation energies, implying that the two clusters possess relatively higher stability. This study also reveals that the Al atom is seen to induce significant changes in the magnetic property of the host cluster. Especially, the magnetic moment of the ScnAl cluster is quenched for n=3, 5, and 7, and the total magnetic moment of the Sc12Al cluster is only 7 mu(B) (but 19 mu(B) for Sc-13).