Inelastic electron dephasing scattering times in disordered metals

We have studied and compared the inelastic electron dephasing scattering times in disordered metals with significantly different characteristics. Both the temperature dependence and electron elastic mean-free-path (l) dependence of the electron-phonon scattering times, τ_ep, are determined from weak-localization studies. Our experimental results suggest that τ_ep^-1 to approximately T² in numerous crystalline disordered dilute Ti_1-xAl_x, dilute Ti_1-xSn_x, Au₅₀Pd₅₀, and Ti₇₃Al₂₇ alloys. However, our results do not support a universal dependence of τ_ep^-1 on l among these various metals. Our observation of the T²-law is in disagreement with current theoretical concept for electron-phonon interaction in disordered metals. In addition, we have inferred the critical electron-electron scattering times, τ_EE, in a number of very low-diffusivity thick Sc, RuO₂, and IrO₂ films. We find that τ_EE^-1 to approximately T and also that τ_EE^-1 is independent of l. This observation is understood in terms of the current theory for inelastic electron-electron scattering in bulk metals near the mobility edge. Our results altogether establish a crossover of the inelastic electron dephasing from electron-phonon scattering to electron-electron scattering as the amounts of disorder greatly increase and the systems move significantly toward the Anderson transition.