Dynamical electron-phonon interaction and conductivity in strongly disordered metal alloys

Abstract

A theory of transport in random metal alloys is presented which focuses on certain model-independent features of the electron-phonon dynamics which have been previously neglected. It is found that in the low-resistivity limit the adiabatic-phonon approximation is valid and the disorder associated with phonons increases the resistivity. In the high-resistivity limit where the weak-scattering approximation breaks down due to incipient Anderson localization, the adiabatic-phonon assumption also fails, and phonons actually assist the mobility, producing an anomalous negative temperature coefficient of resistivity. Model analytical and numerical calculations suggest that this mechanism could be the source of the Mooij correlation between the resistivity and its temperature coefficient. The connection between these results and recent scaling theories of localization is discussed.