Low-temperature electron dephasing time in AuPd revisited

Abstract

Ever since the first discoveries of the quantum-interference transport in mesoscopic systems, the electron dephasing times, T(P, in the concentrated AuPd alloys have been extensively measured. The samples were made from different sources with different compositions, prepared by different deposition methods, and various geometries (ID narrow wires, 2D thin films, and 3D thick films) were studied. Surprisingly, the low-temperature behavior of tau(phi) inferred by different groups over two decades reveals a systematic correlation with the level of disorder of the sample. At low temperatures, where tau(max)(phi) proportional to D-alpha is (nearly) independent of temperature, a scaling T-phi(max) proportional to D-alpha is found, where T-phi(max) is the maximum value of T-phi measured in the experiment, D is the electron diffusion constant, and the exponent alpha is close to or slightly larger than 1. We address this nontrivial scaling behavior and suggest that the most possible origin for this unusual dephasing is due to dynamical structure defects, while other theoretical explanations may not be totally ruled out. (c) 2007 Elsevier B.V. All rights reserved.