title: Strong energy dependence of the electron-phonon coupling strength on Bi(100).
abstract: We have studied the energy dependence of the electron-phonon coupling strength on Bi(100). A fit of the temperature-dependent surface state linewidth results in a change of the coupling parameter lambda from 0.20+/-0.02 to 0.72+/-0.05 as the binding energy of the surface state increases from 70 to 330 meV. This result cannot be reconciled with the usual interpretation of lambda as the electron-phonon mass enhancement parameter at the Fermi energy. We suggest that this behavior is mainly caused by the strong energy dependence of the bulk density of states in this region.
authors.affiliation: Institute for Storage Ring Facilities, University of Aarhus, DK-8000 Aarhus C, Denmark.
authors.forename: J E
authors.initials: JE
authors.lastname: Gayone
authors.forename: S V
authors.initials: SV
authors.lastname: Hoffmann
authors.forename: Z
authors.initials: Z
authors.lastname: Li
authors.forename: Ph
authors.initials: P
authors.lastname: Hofmann