Dresden 2014 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 74: Correlated Electrons: Quantum Impurities, Kondo Physics

TT 74.1: Talk

Wednesday, April 2, 2014, 15:00–15:15, BEY 81

The Kondo model in nonequilibrium: Interplay between voltage and temperature and crossover from weak to strong coupling — Frank Reininghaus, Mikhail Pletyukhov, and •Herbert Schoeller — Institut für Theorie der Statistischen Physik, RWTH Aachen

We analyze the 1-channel spin-1/2 nonequilibrium Kondo model at finite voltage and temperature by using a new formulation of real-time renormalization group with the Laplace variable E as flow parameter [1,3]. If the effective Liouvillian in Laplace space is analytic around E=0 (corresponding to the stationary state), we present convincing arguments that the method is capable of describing reliably the crossover from weak to strong coupling for the stationary conductance as function of voltage and temperature. Besides universal line shapes, we propose an elegant way to determine the Kondo temperature from the voltage dependence of the conductance. Furthermore, for a fixed finite voltage, we find that the temperature-dependence of the differential conductance exhibits non-monotonic behavior. We compare our results with recent experiments and find good agreement [2,3]. For the N-channel Kondo model with N>>1, we calculate the transient dynamics and find a pure power-law decay typical for non-Fermi liquid behaviour.
M. Pletyukhov and H. Schoeller, Phys. Rev. Lett. 108, 260601 (2012)
A.V. Kretinin, H. Shtrikman, and D. Mahalu, Phys. Rev. B 85, 201301(R) (2012)
O. Klochan et al., Phys. Rev. B 87, 201104(R) (2013)