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, ${\tau }_{\varphi }$, 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 thickfilms) were studied. Surprisingly, the low-temperature behavior of ${\tau }_{\varphi }$ inferred by different groups over two decades reveals a systematic correlation with the level of disorder of the sample. At low temperatures, where ${\tau }_{\varphi }$ is (nearly) independent of temperature, a scaling ${\tau }_{\varphi }^{\max }\propto D^{-\alpha }$ is found, where $ta{u}_{\varphi }^{\max }$ is the maximum value of ${\tau }_{\varphi }$ 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.

to appear in Physica E, Proceedings for the International Seminar and Workshop "Quantum Coherence, Noise, and Decoherence in Nanostructures", 15-26 May 2006, Dresden

References in corpus (4)

• Theory of inelastic scattering from magnetic impurities
• Universal dephasing rate due to diluted Kondo impurities
• Quantum decoherence of interacting electrons in arrays of quantum dots and diffusive conductors
• Electronic coherence in metals: comparing weak localization and time-dependent conductance fluctuations