Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 59: Poster Session II (Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: arrays; Nanostructures at surfaces: Wires, tubes; Nanostructures at surfaces: Other; Plasmonics and nanooptics; Metal substrates: Epitaxy and growth; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsoprtion of organic / bio molecules; Metal substrates: Adsoprtion of inorganic molecules; Metal substrates: Adsoprtion of O and/or H; Metal substrates: Clean surfaces; Density functional theory and beyond for real materials)
O 59.109: Poster
Mittwoch, 24. März 2010, 17:45–20:30, Poster B1
Electron-induced emission of correlated electron pairs from Fe(001) — •Franz Giebels1,2, Herbert Gollisch1, and Roland Feder1,2 — 1Theoretische Festkörperphysik,Universität Duisburg-Essen, 47048 Duisburg, Germany — 2Max-Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
As an essential prerequisite we have calculated the electronic structure of the ground state of a thick Fe(001) film by means of an ab initio Full-Potential Linear Augmented-Plane-Wave method. On the basis of the ground state spin densities we constructed effective quasi-particle potentials, which in particular incorporate a spin-dependent mean free path for the primary electron and the two outgoing electrons. Using these potentials and a screened Coulomb interaction model, we calculated (e,2e) equal-energy angular distributions from Fe(001) by means of a Green function formalism involving Coulomb-correlated two-electron states. For primary spin up and down these distributions are resolved according to parallel and antiparallel alignment of the spins of the primary electron and the relevant valence electron. For parallel spins the outgoing two electrons are thus correlated by exchange and Coulomb interaction, whereas for antiparallel spins there is only the Coulomb correlation. The central depletion zones, which we find in the angular distributions, may therefore – with the proviso of some modification by matrix element effects – be viewed as manifestations of an exchange-correlation hole or a correlation hole in momentum space. Like in the well-known real-space case, the former is significantly larger than the latter.