Momentum transfer effects in near surface electron energy loss |
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Authors: | L Calliari S Fanchenko |
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Institution: | 1. European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*‐FBK), Trento, Italy;2. Institute of Informational Technologies, National Research Centre ‘Kurchatov Institute’, Moscow, Russia |
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Abstract: | We examine two formulations for the differential surface excitation parameter (DSEP): one provided by Tung et al. and the other given by the Chen–Kwei position‐dependent differential inverse inelastic mean free path integrated over the electron trajectory. We demonstrate that the latter converges to the former provided that the dielectric function of the solid does not depend on the momentum transfer or it depends on just the momentum transfer component parallel to the surface. Tung's DSEP represents therefore an approximation to the Chen–Kwei DSEP calculated for a dielectric function with no restrictions on the momentum dependence. The approximation is shown to work in the limit of small momentum transfer and to imply an error of 4%–5% for electrons traveling through the solid with energy E = 1 keV. Copyright © 2015 John Wiley & Sons, Ltd. |
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Keywords: | differential surface excitation parameter inelastic scattering electron energy loss momentum transfer surface plasmons Begrenzungs effect |
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