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TT: Tiefe Temperaturen
TT 7: Korrelierte Elektronen: Schwere Fermionen
TT 7.2: Vortrag
Montag, 8. März 2004, 14:45–15:00, H19
Renormalization of the periodic Anderson model: an alternative analytical approach to heavy Fermion behavior — •Klaus Becker1 and Arnd Hübsch1,2 — 1Institut für Theoretische Physik, Technische Universität Dresden, D-01062 Dresden — 2Department of Physics, University of California, Davis, CA 95616, USA
A recently developed projector-based renormalization method (PRM) for many-particle Hamiltonians is applied to the periodic Anderson model with the aim to describe heavy Fermion behavior. In this method high-energetic excitation operators instead of high energetic states are eliminated. We arrive at an effective Hamiltonian for a quasi-free system which consists of two heavy-quasiparticle bands. In contrast to the usual slave boson mean-field (SB) treatment one of the bands describes a subsystem of renormalized but still correlated f electrons whereas the second band stands for renormalized conduction electrons. The resulting renormalization equations for the parameters of the Hamiltonian are valid for large as well as small degeneracy νf of the angular momentum. An expansion in 1/νf is avoided. Within an additional approximation which adapts the idea of a fixed renormalized f level εf, we obtain coupled equations for εf and the averaged f occupation ⟨ nf ⟩. These equations resemble to a certain extent those of the SB theory. In particular, for large νf the results for the PRM and the SB approach agree quite well whereas considerable differences are found for small νf.