Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 43: Correlated Electrons: f-Electron & Heavy Fermion Systems

TT 43.10: Vortrag

Mittwoch, 9. März 2016, 12:00–12:15, H20

Variational cluster approach to superconductivity in the Kondo lattice model — •Benjamin Lenz, Salvatore R. Manmana, and Thomas Pruschke — Institute for Theoretical Physics, Georg-August-Universität Göttingen, Germany

The variational cluster approximation (VCA) allows to study broken symmetry phases of various lattice models at zero temperature. However, most research has been done on electron systems without coupling to additional spins. Here, we investigate the Kondo lattice model (KLM) - a paradigmatic model for heavy fermion materials which contains interactions between electrons and localized spins. We first focus on the antiferromagnetic ground state in the half-filled KLM and compare our finite-size extrapolated VCA results to those of other established techniques, like quantum Monte Carlo. We further ask for the existence of superconductivity at finite doping in this model, motivated by findings for heavy fermion systems and dynamical mean-field theory (DMFT)[1]. We probe the system for s- and d-wave superconductivity and present an analysis of the different ground states which emerge on tuning the electron filling and exchange coupling strength J.
Financial support via DFG through FOR1807 is gratefully acknowledged.
O. Bodensiek, R. Zitko, M. Vojta, M. Jarrell, and T. Pruschke,

PRL 110, 146406 (2013)