Electron-phonon contribution to the thermopower of metals

A theorem is proved for the thermopower when limited by the electron-phonon interaction. It is shown for simple metals that the thermopower is given by the Mott formula plus a correction term. The correction term is evaluated and shown to be small for simple metals. Thus we are able to show that Mott's formula is valid for phonon scattering by electrons, even when the energy dependence of the phonons is taken into account. This proof extends our earlier result, which only applied to static impurities, and to phonons in the adiabatic approximation.