Electron coherence at low temperatures: The role of magnetic impurities

Laurent Saminadayar (1) , Pritiraj Mohanty (2) , Richard A. Webb (3) , Pascal Degiovanni (2, 4) , Christopher Bäuerle (5)

1 TPS - Thermodynamique et biophysique des petits systèmes
2 Department of Physics [Boston]
3 USC Nano Center
4 Phys-ENS - Laboratoire de Physique de l'ENS Lyon
5 QuantECA - Circuits électroniques quantiques Alpes

We review recent experimental progress on the saturation problem in metallic quantum wires. In particular, we address the influence of magnetic impurities on the electron phase coherence time. We also present new measurements of the phase coherence time in ultra-clean gold and silver wires and analyse the saturation of \tauphi in these samples, cognizant of the role of magnetic scattering. For the cleanest samples, Kondo temperatures below 1 mK and extremely-small magnetic-impurity concentration levels of less than 0.08 ppm have to be assumed to attribute the observed saturation to the presence of magnetic impurities.

Keywords: weak localization; decoherence; mesoscopic physics; Kondo effect

Domains: Physics [physics]; Condensed Matter [cond-mat]; Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]

Laurent Saminadayar, Pritiraj Mohanty, Richard A. Webb, Pascal Degiovanni, Christopher Bäuerle. Electron coherence at low temperatures: The role of magnetic impurities. Physica E: Low-dimensional Systems and Nanostructures, 2007, 40 (1), pp.12. ⟨10.1016/j.physe.2007.05.026⟩. ⟨ensl-00179758⟩