LOCAL MAGNETIC-PROPERTIES AND ELECTRONIC-STRUCTURES OF 3D AND 4D IMPURITIES IN CU CLUSTERS

The local magnetic properties and electronic structures of Cu(12)R clu sters with I-h and O-h symmetries (R=Sc, Ti, V, Cr, Mn, Fe, Co, Wi, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, and Ag) have been systematically studied with the density-functional formalism, and the Kohn-Sham equation is s olved self-consistently with the discrete variational method. By calcu lating the binding energies for 3d series, we find that the icosahedra l structure is more stable than the octahedron structure. Pd and Ag do ping can enhance the stability of a cluster, and the alloying effects in such doped clusters have an important effect on binding energy. The electronic structures calculated in equilibrium configurations show t hat the clusters with R=Cu, Cr, Mo, or Ae have closed electronic shell s, while the others have open electronic shells. In particular. we hav e performed comprehensive calculations on the local magnetism of impur ities in a cluster, and found that the behavior of local magnetism for 3d and 4d impurities in Cu-12 clusters is different from that in bulk as well as from that in Al-12 clusters. In contrast to the d-d intera ction picture for local magnetism in the d-band bulk host, we have fou nd that there are more complicated interactions acting in clusters to affect the local magnetism of impurities: the interactions of the Cu-g orbital with R-spd orbitals play a crucial role on the local magnetic moment for impurities with more than a half-filled d shell, such as M n, Fe, Co, Ni, Tc, Ru, and Rh; the interactions of the Cu-d orbital wi th R-spd orbitals contribute to the local magnetic moment for impurite s with a less than half-filled d shell, such as Sc, Ti, V, Y, Zr, and Nb. Wt have also tested and discussed the Stonor-like criterion for th e occurrence of a local moment in a cluster.