Dresden 2017 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 30: Correlated Electrons: Quantum Impurities, Kondo Physics

TT 30.3: Talk

Tuesday, March 21, 2017, 14:30–14:45, HSZ 03

Interplay of Superconductivity and Magnetism in the 2D Kondo Lattice Model: A Variational Cluster Approach — •Benjamin Lenz, Riccardo Gezzi, and Salvatore R. Manmana — Institute for Theoretical Physics, Georg-August-Universität Göttingen

We present results for the interplay of d-wave superconductivity and antiferromagnetism in the Kondo lattice model using the variational cluster approximation (VCA). Both the paramagnetic and the antiferromagnetic phase of the model are investigated and regions with different Fermi surface topology are found in the latter. The transition between these two different antiferromagnetic phases is investigated close to and off half-filling. VCA is used to probe the system for s-wave and d-wave superconductivity for all coupling regions. It is shown that only by treating antiferromagnetism and superconductivity on equal footing artificial superconducting solutions at half-filling can be avoided. No true s-wave superconducting solutions due to correlation effects are found, but d-wave pairing proves to be robust for various coupling strengths off half-filling. Its interplay with antiferromagnetism is analyzed at weak coupling.