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TT: Fachverband Tiefe Temperaturen

TT 23: Correlated Electrons: (General) Theory

TT 23.14: Vortrag

Mittwoch, 27. Februar 2008, 17:45–18:00, H 0104

Rotationally invariant slave-boson formalism and momentum dependence of the quasiparticle weight — •Frank Lechermann¹, Antoine Georges², Gabriel Kotliar³, and Olivier Parcollet⁴ — ¹I. Institut für Theoretische Physik, Universität Hamburg, Germany — ²CPHT, École Polytechnique, Palaiseau, France — ³Serin Physics Laboratories, Rutgers University, NJ, USA — ⁴Service de Physique Théorique, CEA Saclay, Gif-Sur-Yvette, France

The rotationally invariant formulation of the slave-boson formalism is generalized to multiorbital models, with arbitrary interactions, crystal fields, and multiplet structure [1]. This allows for the study of multiplet effects on the nature of low-energy quasiparticles. Nondiagonal components of the matrix of quasiparticle weights can be calculated within this framework. When combined with cluster extensions of dynamical mean-field theory, this method renders it possible to address the effects of spatial correlations, such as the generation of the superexchange and the momentum dependence of the quasiparticle weight. The method is illustrated on several examples, including a two-dimensional single-band Hubbard model (within a two-site cellular dynamical mean-field approximation).

[1] F. Lechermann, A. Georges, G. Kotliar, and O. Parcollet, PRB 76 155102 (2007).