Effects of finite bandwidth on spectroscopic characteristics of normal metals

We analyze features that appear in spectroscopic characteristics of normal metals due to a finite width of the electronic band. Electronic self-energy, renormalized density of states, optical scattering rate, and optical mass enhancement parameter are computed for the cases when the electrons are coupled to either impurities or phonons. The most significant effect of impurity scattering is broadening of the electronic band. For phonon scattering, modifications arise both on the phonon and band edge energy scales. The results contrast sharply with those for an infinite band, the approximation often employed for metals with a wide conduction band.