Iron impurities in gold and silver: Comparison of transport measurements to numerical renormalization group calculations exploiting non-Abelian symmetries

Abstract

We consider iron impurities in the noble metals gold and silver and compare experimental data for the resistivity and decoherence rate to numerical renormalization group results. By exploiting non-Abelian symmetries, we show improved numerical data for both quantities as compared to previous calculations [Costi et al., Phys. Rev. Lett. 102, 056802 (2009).], using the discarded weight as criterion to reliably judge the quality of convergence of the numerical data. In addition, we also carry out finite-temperature calculations for the magnetoresistivity of fully screened Kondo models with $S=\frac{1}{2}$, 1, and $\frac{3}{2}$, and compare the results with available measurements for iron in silver, finding excellent agreement between theory and experiment for the spin-$\frac{3}{2}$ three-channel Kondo model. This lends additional support to the conclusion of Costi et al. that the latter model provides a good effective description of the Kondo physics of iron impurities in gold and silver.