Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 111: Correlated Electrons: Quantum Impurities, Kondo Physics
TT 111.6: Talk
Friday, March 20, 2015, 11:00–11:15, H 3005
Correlation effects in the extended Anderson model — •David Hämmerle1, Lukas Merker2, Theo A. Costi2, and Sabine Andergassen1,3 — 1Universität Wien — 2Forschungszentrum Jülich — 3Universität Tübingen
We investigate the single-impurity Anderson model with an on-site Coulomb interaction U supplemented by UL/R′ between the dot and the leads. Using the functional renormalization group in the static approximation we compute the linear conductance and the charge and spin susceptibilities at T=0. The accuracy of our results is assessed by a comparison to NRG calculations. We analyze the physical behavior resulting from the competition between the Kondo effect and the characteristic power-laws of the interacting resonant level model. We find that for increasing UL/R′ the effective on-site repulsion is reduced leading initially to an enhancement of the Kondo temperature. For sufficiently large UL/R′, at particle-hole symmetry the low-energy properties resemble the ones of a charge Kondo effect as obtained for an attractive Coulomb interaction, while away from particle-hole asymmetry a power-law behavior as for the interacting resonant level model is observed. For a more realistic modelling of a molecular quantum dot we include an additional local Coulomb interaction in the leads, which lead to novel signatures in the conductance line shape.