Münster 1997 – wissenschaftliches Programm
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O: Oberflächenphysik
O 6: POSTER I
O 6.1: Poster
Montag, 17. März 1997, 14:15–15:45, AULA
A First Glimpse on the Scattering Dynamics of Low Energy Electrons on the Valence Electrons of W(100) — •O.M. Artamonov1, S.N. Samarin1, H. Schwabe1, and J. Kirschner1, H. Gollisch2, D. Meiner2, and R. Feder2 — 1Max-Planck-Institut für Mikrostrukturphysik, Halle — 2Universität Duisburg, Duisburg
Coincidence electron spectroscopy from solid surfaces in the reflection geometry allows the selection of single scattering events of the primary electron with a valence electron of the solid and the complete determination of the electron-electron scattering dynamics. For primary electron energies 10 - 40 eV, we measured the electron pair creation probability versus the binding energy of the valence electron and the energy sharing probability between correlated electrons of the pair for the W(100) single crystal. A theoretical approach is presented, which starts from a relativistic distorted-wave Born approximation including exchange. The relevant four electron states are calculated as full multiple scattering solutions of the Dirac equation for a semi-infinite crystalline system. Screened Coulomb matrix elements between these states are then evaluated to obtain the observable scattering cross section. Experiment and theory show that the pair creation probability is maximal when the primary electron collides with an electron near the Fermi energy. The energy sharing probability for correlated electrons of the pair depends on the elastic scattering conditions of the primary electrons and on the experimental geometry.