Density Functional Theory Calculations for the Structural, Electronic, and Magnetic Properties of (Gd2O3)n0,±1 Clusters with n=1-10

The structural stability and electronic and magnetic properties of stoichiometric (Gd(2)O3)n clusters with n = 1-10 were investigated using spin-polarized density functional theory through the broken-symmetry approach. Size-induced changes in the point symmetry of these clusters were observed. A large coordination number led to elongation of Gd-O bonding. Either adding an electron to or removing an electron from the ground state of a neutral cluster brought significant changes in the van der Waals volume for clusters n = 1-3. Binding energy increased with cluster size. However, the highest occupied molecular orbital-lowest unoccupied molecular orbital gap, ionization, and electron affinity fluctuated when n increased from 1 to 10. Natural population analysis and partial density of states revealed that the Gd-4f orbital hardly participated in bonding and that the Gd-5d/6s/6p orbitals were hybrid with the O-2p orbitals. The competition between Ruderman-Kittel-Kasuya-Yosida-type and superexchange-type interactions resulted in the magnetic oscillation of clusters between antiferromagnetic and ferromagnetic states. We also found similar behavior in the various structures of Gd12O18. The ground state was easily activated to the excited state because the antiferromagnetic and ferromagnetic coupling states were nearly identical in energy.