Effect of disorder on the quantum coherence in mesoscopic wires

• Published in: Physical review letters Vol. 102; no. 22; p. 226801
• Main Authors: Niimi, Y, Baines, Y, Capron, T, Mailly, D, Lo, F-Y, Wieck, A D, Meunier, T, Saminadayar, L, Bäuerle, C
• Format: Journal Article
• Language: English
• Published: United States American Physical Society 05-06-2009
• Subjects: Condensed Matter; Other; Physics
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/physrevlett.102.226801

We present phase coherence time measurements in quasi-one-dimensional mesoscopic wires made from high mobility two-dimensional electron gas. By implanting gallium ions into a GaAs/AlGaAs heterojunction we are able to vary the diffusion coefficient over 2 orders of magnitude. We show that in the diffusive limit, the decoherence time follows a power law as a function of diffusion coefficient as expected by theory. When the disorder is low enough so that the samples are semiballistic, we observe a new and unexpected regime in which the phase coherence time is independent of disorder. In addition, for all samples the temperature dependence of the phase coherence time follows a power law down to the lowest temperatures without any sign of saturation and this strongly suggests that the frequently observed low temperature saturation is not intrinsic.