Electron–phonon contribution to the phonon and excited electron (hole) linewidths in bulkPd

Abstract

We present an ab initio study of the electron–phonon (e–ph) coupling and itscontribution to the phonon linewidths and to the lifetime broadening of excitedelectron and hole states in bulk Pd. The calculations, based on density-functionaltheory, were carried out using a linear-response approach in the plane-wavepseudopotential representation. The obtained results for the Eliashberg spectral functionα2F(ω), e–ph couplingconstant λ, and the contribution to the lifetime broadening,Γe−ph, show strong dependence on both the energy and momentum of an electron (hole)state. The calculation of phonon linewidths gives, in agreement with experimentalobservations, an anomalously large broadening for the transverse phonon modeT1 inthe Σ direction. In addition, this mode is found to contribute most strongly to the electron–phononscattering processes on the Fermi surface.