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Scaling of the low temperature dephasing rate in Kondo systems

F. Mallet·J. Ericsson·D. Mailly·S. Unlubayir·D. Reuter·A. Melnikov·A. D. Wieck·T. Micklitz·A. Rosch·T. A. Costi·L. Saminadayar·C. Bauerle
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Abstract

We present phase coherence time measurements in quasi-one-dimensional Ag wires doped with Fe Kondo impurities of different concentrations $n_s$. Due to the relatively high Kondo temperature $T_{K}\approx 4.3K$ of this system, we are able to explore a temperature range from above $T_{K}$ down to below $0.01 T_{K}$. We show that the magnetic contribution to the dephasing rate $γ_m$ per impurity is described by a single, universal curve when plotted as a function of $(T/T_K)$. For $T>0.1 T_K$, the dephasing rate is remarkably well described by recent numerical results for spin $S=1/2$ impurities. At lower temperature, we observe deviations from this theory. Based on a comparison with theoretical calculations for $S>1/2$, we discuss possible explanations for the observed deviations.

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F. Mallet, J. Ericsson, D. Mailly, S. Unlubayir, D. Reuter, A. Melnikov, A. D. Wieck, T. Micklitz, A. Rosch, T. A. Costi, L. Saminadayar, C. Bauerle. 2006-07-06. Scaling of the low temperature dephasing rate in Kondo systems. https://doi.org/10.1103/physrevlett.97.226804

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