Energy Bands in Ferromagnetic Nickel

The tight-binding method has been employed to calculate energy bands in ferromagnetic nickel. The basis set consisted of atomic wave functions for the $1s$, $2s$, $3s$, $4s$, $2p$, $3p$, and $4p$ states, expressed as linear combinations of Gaussian orbitals, and five individual Gaussian orbitals for each $3d$ state. The Coulomb part of the crystal potential was constructed from a superposition of overlapping neutral-atom charge densities, the atoms being in the d⁹s¹ configuration. The Xα method of Slater et al. was used to construct an exchange potential. Energy levels were calculated at 1505 points in 1/48th of the Brillouin zone. The results are generally in good agreement with those obtained from other first-principles calculations. The properties for several positions on the Fermi surface are determined and compared with experiment. The spin splitting of the d bands is calculated to be about 0.8 eV. A spin-wave reciprocal effective mass of 0.165 (in atomic units) is obtained.