Inelastic phase-coherence time in thin metal films

We obtain the inelastic phase-coherence time τ_φ for thin metal films above helium temperature by considering Coulomb and electron-phonon scattering contributions. In this temperature regime, we find the asymptotic expansion used so far for the electron-phonon contribution to be invalid. The resulting T dependence is not a power law, but mimics Tᵖ with p2 for T=4-20 K. Our calculated disorder dependence is very weak. We interpret the experimental results of Bergmann and collaborators as a superposition of Coulomb and a two-dimensional electron-phonon contribution. We obtain good agreement between theory and experiment for τ_φ as a function of both temperature and resistivity.