Effect of disorder on the quantum coherence in mesoscopic wires.
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.
Niimi
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Y
Institut Néel, CNRS, B.P. 166, 38042 Grenoble Cedex 09, France.
Baines
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Y
Capron
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T
Mailly
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D
Lo
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Wieck
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AD
Meunier
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T
Saminadayar
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L
Bäuerle
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