Quasiparticle properties of a simple metal at high electron temperatures

We compute the real and imaginary parts of the quasiparticle self-energy Σ due to the electron-electron interaction for electrons and holes in jellium and crystalline Al at electron temperatures approaching the Fermi temperature TF. ReΣ and ImΣ are computed using a finite temperature generalization of the GW approximation. We find a decrease in the electron lifetime and an increase in the valence and conduction bandwidths as T is increased. Calculation of the spectral function $A(k,E)$ reveals that the total weight in the quasiparticle peak is a very weak function of T, and that the basic peak structure remains for T~few×0.1TF. These predictions suggest that at these electron temperatures, the prominent peak in the absorption spectrum of Al at ~1.5 eV should be washed out due to lifetime broadening, even if the ions remain in their crystalline positions.