Berlin 2015 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 110: Superconductivity: Fe-based Superconductors – Theory
TT 110.4: Vortrag
Freitag, 20. März 2015, 10:15–10:30, H 2053
Coherence-incoherence crossover and non-Fermi-liquid self-energy in Hund's metals - Insights into the normal state of iron pnictide superconductors from a Numerical Renormalization Group study — •Katharina M. Stadler1, Andreas Weichselbaum1, Jan von Delft1, and Gabriel Kotliar2 — 1Faculty of Physics, Ludwig-Maximilians-Universität München — 2Department of Physics and Astronomy, Rutgers University, NJ, USA
In 2008, the iron pnictides were discovered as a new class of strongly correlated high-temperature superconductors [1]. The normal state of these itinerant multi-band materials shows characteristic anomalous properties, which are assigned to a coherence-incoherence crossover at very low temperatures, mediated by Hund's rule coupling.
We study a N-channel Anderson impurity model with Hund's coupling and a filling of N-1, together with the corresponding Kondo model, for the cases N=2 and 3, using the full density-matrix Numerical Renormalization Group (fdmNRG) with non-abelian symmetries [2]. Our high-quality real-frequency NRG results confirm the existence of a Fermi-liquid regime at low temperatures and a non-Fermi-liquid power-law for the self-energy in the incoherent normal state. Further, we analyse the interplay of spin and orbital degrees of freedom to gain insights into the relevant energy scales of the coherence-incoherence crossover and the corresponding renormalization group flow. In addition the lattice model is investigated within DMFT employing fdmNRG as impurity solver.
[1] Takahashi et al., Nature 453 (2008).
[2] A. Weichselbaum, Ann.Phys. 327 (2012).