Transition-metal impurities in CoGa

Self-consistent embedded cluster models are developed to describe the electronic structure of CoGa, and of isolated transition-metal impurities (Ti, V, Cr) in CoGa. First-principles local-density theory is used in a variational linear combination of atomic orbitals framework to obtain effective charge and spin configurations of host and impurity atoms. 9, 15, and 27 atom clusters are considered; charge configurations are somewhat sensitive to cluster size, and spurious spin polarization of peripheral Co atoms is observed in the smaller clusters. The large-cluster results are consistent with experimental interpretations.