Anomalous temperature and disorder dependences of electron-phonon scattering rate in impure V_1-xAl_x alloys

Using weak-localization studies, we have measured the electron-phonon scattering time τ_ep in a series of V_1-xAl_x alloys having the characteristic of ql ≪ 1, where q is the wave number of the thermal phonons and l is the electron elastic mean free path. We find an anomalous electron-phonon scattering rate obeying a quadratic temperature dependence as well as a linear mean-free-path dependence, i.e., τ_ep^-1∼T²l. This result cannot be explained in terms of existing theories for the electron-phonon interaction in impure conductors.