Berlin 2012 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 49: Joint Session "Surface Magnetism III" (jointly with O)
MA 49.14: Vortrag
Donnerstag, 29. März 2012, 18:45–19:00, BH 243
Spin-dependent two-electron emission from ferromagnetic Fe(001) — •Jürgen Kirschner1, Frank O. Schumann1, Carsten Winkler1, Franz Giebels2, Herbert Gollisch2, and Roland Feder2 — 1Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle — 2Theoretische Festkörperphysik, Universität Duisburg-Essen, 47048 Duisburg
We present a joint experimental and theoretical study of correlated electron pair emission from a ferromagnetic Fe(001) surface induced by spin-polarized low-energy electrons [1]. Spin-dependent angular and energy distributions of the emitted pairs have been measured and calculated. They are analyzed with the aid of the spin-, momentum-, symmetry-, and layer-resolved valence electron density of states, which we obtained by an ab-initio density functional theory calculation. The observed spectra are found to arise almost completely from only three surface parallel atomic layers. Momentum distributions for parallel spins of the emitted electrons exhibit an exchange-correlation hole, which is larger than the correlation hole in the antiparallel spin case. By comparing experimental antiparallel-spin pair spectra with their theoretical counterparts we determine an effective screening strength of the Coulomb interaction in the surface region.