Momentum-resolved lifetimes of image-potential States on cu(100).
The dependence of the inelastic lifetime of electrons in the image-potential states of Cu(100) on their momentum parallel to the surface has been studied experimentally by means of time- and angle-resolved two-photon photoemission and theoretically by evaluating the electron self-energy within the GW approximation. The pronounced decrease of the n = 1 lifetime from 40 fs at normal emission (k(parallel) = 0) to 20 fs for k(parallel) = 0.33 A(-1) cannot be accounted for by interband decay processes to bulk states. We show that intraband transitions within the image-state band give a contribution to this decrease comparable in magnitude with the interband channel.
Berthold
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W
Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, D-35032 Marburg, Germany.
Höfer
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Feulner
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Chulkov
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Silkin
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Echenique
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