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O: Oberflächenphysik

O 13: Postersitzung (Adsorption auf Oberfl
ächen, Oberfl
ächenreaktionen, Elektronische Struktur, Epitaxie und Wachstum, Halbleiteroberfl
ächen und Grenzfl
ächen, Oxide und Isolatoren)

O 13.37: Poster

Montag, 26. März 2001, 19:00–22:00, Foyer zu B

Studying Spin Dependent Electronic Excitations by Electron Coincidence Spectroscopy — •A. Morozov, S.N. Samarin, J. Berakdar, F.U. Hillebrecht , and J. Kirschner — Max-Planck-Institut fur Mikrostrukturphysik, Weinberg 2, 06120 Halle.

In electron coincidence spectroscopy, inleastically scattered electrons are detected in concidence with those electrons to which the energy is transferred in the scattering event. We detect electron pairs after excitation by polarized electrons in two ime-of-flight detectors of 75 mm diameter active area [1]. In the final state, a hole is created in the sample, relating this experiment to photoemission. Conservation rules determine energy and momentum of this hole. This allows to probe different regions in the Brillouin zone. If the sum of the kinetic energies of the two electrons equals the primary energy (reduced by the work function), the hole is at the Fermi level, and spin asymmetries in the scattering arise from the spin polarization at the Fermi level. The energy sharing between the two electrons gives information on the nature and properties of the correlation between the two electrons. We find that the energy sharing depends on the energy, spin and momentum of the hole created in the process. 1. S.N. Samarin, J. Berakdar, O. Artamonov, and J. Kirschner, Phys. Rev. Lett. 85, 1746 (2000).