Electronic structure of Ni and Mo silicides investigated by x-ray emission spectroscopy and density functional theory

We report a combined study of the electronic structure of NiSi(2), Ni(2)Si, MoSi(2), and Mo(5)Si(3) using x-ray emission spectroscopy and density functional theory. The local and partial metal d and Si p and sd densities of states (DOSs) are obtained for the four compounds both experimentally and theoretically. This allows refined insight into the Si-metal bonding interaction, shown to be determined by a competition between the effects of the lattice structure and of the spatial extent of the metal d wave function. The latter effect is found to prevail for all four compounds, based on the prominent Si-Mo pd hybridization found in the DOS of MoSi(2) and Mo(5)Si(3) and the dominant Ni-Ni dd interaction observed in the electronic structure of NiSi(2) and Ni(2)Si.