Theory of spin-resolved Auger-electron spectroscopy of ferromagnetic 3d-transition metals

Core-valence-valence Auger electron spectra are calculated for a multiband Hubbard model including correlations among Valence electrons as well as cor relations between core and valence electrons. The interest is focused on th e ferromagnetic 3d-transition metals. The Auger line shape is calculated fr om a three-particle Green function. A realistic one-particle input is taken from tight-binding band-structure calculations. Within a diagrammatic appr oach we can distinguish between the direct correlations among those electro ns participating in the Auger process and the indirect correlations in the rest system. The indirect correlations are treated within second-order pert urbation theory for the self-energy. The direct correlations are treated us ing the valence valence ladder approximation and the first-order perturbati on theory with respect to valence-valence and care-valence interactions. Th e theory is evaluated numerically for ferromagnetic Ni. We discuss the spin -resolved quasiparticle band structure and the Auger spectra and investigat e the influence of the core hole.