Electronic structure of Ni3Al and Ni3Ga alloys

This work investigates the charge transfer and Al (Ga) p-Ni d hybridization effects in the intermetallic Ni3Al (Ni3Ga) alloy using the Ni L-3,L-2- and K-edge and Al (Ga) K x-ray absorption near edge structure (XANES) measurem ents. We find that the intensity of white-line features at the Ni L-3,L-2-e dge in the Ni3Al (Ni,Ga) alloy decreased in comparison with that of pure Ni , which can be attributed to the enhancement of Ni 3d states filling and th e depletion of the density of Ni 3d unoccupied states in the Ni3Al (Ni3Ga) alloy. Two clear features are also observed in the Ni3Al (Ni3Ga) XANES spec trum at the Al (Ga) K-edge, which can be assigned to the Al (Ga) unoccupied 3p (4p) states and their hybridized slates with the Ni 3d/4sp states above the Fermi level in Ni3Al (Ni3Ga). The threshold at Al K-edge XANES for Ni3 Al clearly shifts towards higher photon energies relative to that of pure A l, indicating that Al loses charges upon forming Ni(3)AI. On the other hand , the Ni K-edge shifts towards lower photon energies in Ni3Al (Ni3Ga) relat ive to that of pure Ni, which is consistent with the results of the Al K-ed ge XANES spectrum and is indicative of a charge transfer from Al to Ni site s. Our data support that no significant net charge flow occurs on and off s ites in Ni3Al (Ni3Ga).