Effects of Core-Hole Screening on Spin-Polarised Auger Spectra from Ferromagnetic Ni

We calculate the spin- and temperature-dependent local density of states for ferromagnetic Ni in the presence of a core hole at a distinguished site in the lattice. Correlations among the valence electrons and between valence and core electrons are described within a multi-band Hubbard model which is treated by means of second-order perturbation theory around the Hartree-Fock solution. The core-hole potential causes strong screening effects in the Ni valence band. The local magnetic moment is found to be decreased by a factor of 5-6. The consequences for the spin polarisation of CVV Auger electrons are discussed.