Quasiparticle lifetimes in pure Al and Pb

We present results of theoretical calculations of the quasiparticle lifetimes in pure Al and Pb which are due to the electron-phonon interaction. A four-plane-wave model is used to describe the electronic structure and the coupling with the phonons. The lattice dynamics is taken from inelastic neutron scattering data. At a given temperature (T) the lifetimes (τ) display considerable variation with position on the Fermi surface (FS). At several points on the FS we obtain through a least-squares fit to our numerical output on the low temperature variation of τ, the best power law of the form AT^α with A and α constants. The exponent α is found to vary significantly from point to point.