Inelastic electron dephasing scattering times in disordered metals

Abstract

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 (I) dependence of the electron-phonon scattering times, tau(ep), are determined from weak-localization studies. Our experimental results suggest that tau(ep)(-1) similar to T-2 in numerous crystalline disordered dilute Ti1-xAlx, dilute Ti1-xSnx, Au50Pd50, and Ti73Al27 alloys. However, our results do not support a universal dependence of tau(ep)(-1) on l among these various metals. Our observation of the T-2-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, tau(EE), in a number of very low-diffusivity thick Sc, RuO2, and IrO2 films. We find that tau(EE)(-1) similar to T and also that tau(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. (C) 2000 Elsevier Science B.V. All rights reserved.