Abstract
We investigate the half metallicity and localized spin magnetic moments for individual nanoclusters of zinc-blende transition-metal pnictides and chalcogenides (, Cr, and Mn; , P, As, Sb, S, Se, and Te) using first-principles molecular-orbital calculations. These nanoclusters, as well as the bulk, show half-metallic ferromagnetic behavior for a wide range of bond lengths; otherwise, an antiferromagnetic arrangement is stabilized. The total magnetic moment of an isolated half-metallic nanocluster turns out to be in units of , where is the total number of valence electrons per formula unit, for pnictides, and for chalcogenides. This dependence results from anion dangling hybrids on the cluster surface. Induced antiparallel magnetic moments at anion sites are interpreted in terms of a bond-orbital model; the hybridization effect between cation states and anion states creates holes in the majority-spin states of the bond orbitals. When the nanocluster is embedded in a lattice-matched compound semiconductor with a common anion, the total moment approaches . Half metallicity is maintained at the boundary sites of the nanocluster without any sign of interface states, suggesting the Ohmic nature of the contact.
2 More- Received 27 January 2004
DOI:https://doi.org/10.1103/PhysRevB.69.214429
©2004 American Physical Society