Electron-phonon interaction and lattice thermal conductivity

Phonons in a metal have a finite lifetime due to the emission of electron-hole pairs. This process leads to an electron-phonon contribution Wₑₚᵖ to the thermal resistance, which limits the lattice thermal conductivity κₚ. We present a summary of the available experimental data on Wₑₚᵖ, emphasizing uncertainties and contrasting results from different types of experiments. Methods of obtaining better data are suggested. We show that the available data are in fair agreement with a simple theoretical estimate lim(T→O)Wₑₚᵖ(TθD)²=0.42 Ωₐ1/3Nλ(K cm/W), where Ωₐ is the atomic volume in ³, N is the Fermi-energy density of states (1 spin) in states/eV, and λ is the electron-phonon mass enhancement. The fact that most of the experimental points fall below this estimate is probably the result of anisotropy and mode dependence of the electron-phonon coupling.