Low-temperature electron dephasing time in AuPd revisited

Ever since the first discoveries of the quantum-interference transport in mesoscopic systems, the electron dephasing times, τϕ, 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 (1D narrow wires, 2D thin films, and 3D thick films) were studied. Surprisingly, the low-temperature behavior of τϕ inferred by different groups over two decades reveals a systematic correlation with the level of disorder of the sample. At low temperatures, where τϕ is (nearly) independent of temperature, a scaling τϕmax∝D-α is found, where τϕmax is the maximum value of τϕ measured in the experiment, D is the electron diffusion constant, and the exponent α 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.