Dephasing of electrons in mesoscopic metal wires

By F. Pierre, A. Gougam, A. Anthore, H. Pothier, D. Estève, N. Birge. 2003

170 citations recorded by the source corpus.

We have extracted the phase coherence time t f of electronic quasiparticles from the low field magnetoresistance of weakly disordered wires made of silver, copper, and gold. In samples fabricated using our purest silver and gold sources, t f increases as T 22/3 when the temperature T is reduced, as predicted by the theory of electron‐electron interactions in diffusive wires. In contrast, samples made of a silver source material of lesser purity or of copper exhibit an apparent saturation of t f starting between 0.1 and 1 K down to our base temperature of 40 mK. By implanting manganese impurities in silver wires, we show that even a minute concentration of magnetic impurities having a small Kondo temperature can lead to a quasisaturation of t f over a broad temperature range, while the resistance increase expected from the Kondo effect remains hidden by a large background. We also measured the conductance of Aharonov‐Bohm rings fabricated using a very pure copper source and found that the amplitude of the h/e conductance oscillations increases strongly with magnetic field. This set of experiments suggests that the frequently observed ‘‘saturation’’ of t f in weakly disordered metallic thin films can be attributed to spin‐flip scattering from extremely dilute magnetic impurities, at a level undetectable by other means.

Subfields: Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/fef38425b3bea4081bd499413729da94eab4299e

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In Atomic and Molecular Physics, and Optics

Citations in the corpus

Numerical renormalization group method for quantum impurity systems (2007, background): “…to the inelastic scattering time, τinel(ω, T ) ∼ σ−1inel, is the dephasing time, τφ(T ), for electrons scattering from magnetic impurities and measured in weak-localization experiments on diffusive conductors (Bäuerle et al., 2005; Mohanty et al., 1997; Pierre et al., 2003; Schopfer et al., 2003).”
Mesoscopic Physics of Electrons and Photons (2007, background): “which leads to a temperature dependence in the magnetic scattering time τm(T ) of the form [131] 1 τm(T ) = ni 2πρ0 π2S(S + 1) ln2 T TK + π2S(S + 1) .”