Costi T A, Bergqvist L, Weichselbaum A, von Delft J, Micklitz T, Rosch A, Mavropoulos P, Dederichs P H, Mallet F, Saminadayar L, Bäuerle C
Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany.
Phys Rev Lett. 2009 Feb 6;102(5):056802. doi: 10.1103/PhysRevLett.102.056802. Epub 2009 Feb 3.
We exploit the decoherence of electrons due to magnetic impurities, studied via weak localization, to resolve a long-standing question concerning the classic Kondo systems of Fe impurities in the noble metals gold and silver: which Kondo-type model yields a realistic description of the relevant multiple bands, spin, and orbital degrees of freedom? Previous studies suggest a fully screened spin S Kondo model, but the value of S remained ambiguous. We perform density functional theory calculations that suggest S=3/2. We also compare previous and new measurements of both the resistivity and decoherence rate in quasi-one-dimensional wires to numerical renormalization group predictions for S=1/2, 1, and 3/2, finding excellent agreement for S=3/2.
