title: Low-energy properties of the Kondo lattice model.
abstract: We study the zero-temperature properties of the Kondo lattice model within the dynamical mean-field theory. As an impurity solver we use the numerical renormalization group. We present results for the paramagnetic case showing the anticipated heavy-fermion physics, including direct evidence for the appearance of a large Fermi surface for antiferromagnetic exchange interaction. Allowing for the formation of a Néel state, we observe at finite doping an antiferromagnetic metal below a critical exchange interaction, which shows a crossover from a local moment antiferromagnet with a small Fermi surface for weak exchange coupling to a heavy-fermion antiferromagnet with a large Fermi surface for increasing exchange. Including lattice degrees of freedom via an additional Holstein term we observe a significant suppression of the Kondo effect, leading to a strongly reduced low-energy scale. For too large electron-phonon coupling we find a complete collapse of the heavy Fermi liquid and the formation of polarons.
authors.affiliation: Institute for Theoretical Physics, University of Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Bodensiek
authors.forename: R
authors.initials: R
authors.lastname: Zitko
authors.forename: R
authors.initials: R
authors.lastname: Peters
authors.forename: T
authors.initials: T
authors.lastname: Pruschke