Theory of Spin-Resolved Auger-Electron Spectroscopy from Ferromagnetic 3d-Transition Metals

摘要

CVV Auger electron spectra are calculated for a multi-band Hubbard modelincluding correlations among the valence electrons as well as correlationsbetween core and valence electrons. The interest is focused on theferromagnetic 3d-transition metals. The Auger line shape is calculated from athree-particle Green function. A realistic one-particle input is taken fromtight-binding band-structure calculations. Within a diagrammatic approach wecan distinguish between the \textit{direct} correlations among those electronsparticipating in the Auger process and the \textit{indirect} correlations inthe rest system. The indirect correlations are treated within second-orderperturbation theory for the self-energy. The direct correlations are treatedusing the valence-valence ladder approximation and the first-order perturbationtheory with respect to valence-valence and core-valence interactions. Thetheory is evaluated numerically for ferromagnetic Ni. We discuss thespin-resolved quasi-particle band structure and the Auger spectra andinvestigate the influence of the core hole.