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TT: Fachverband Tiefe Temperaturen

TT 32: Correlated Electrons: Poster Session

TT 32.5: Poster

Thursday, February 28, 2008, 14:00–18:00, Poster B

Properties of a molecular 3-level impurity coupled to a fermionic bath — •Jon-Olaf Krisponeit, Frithjof B. Anders, and Gerd Czycholl — Institut für Theoretische Physik, Universität Bremen

We examine a molecular impurity, consisting of three local orbitals coupled to a fermionic bath. The Coulomb repulsion U and a ferromagnetic Hund’s exchange coupling J>0 between the local electrons are taken into account.

Thermodynamic as well as transport properties are calculated using the numerical renormalization group (NRG). We analyze their dependencies on the level positions, the temperature T and the strength of Hund’s coupling J. We identify the fixed points, the corresponding quantum phase transitions and the scaling laws involved. The parameter dependence of the low temperature crossover scale T₀ is given. Furthermore the influence of an asymmetric coupling strength between bath and impurity is discussed.