Springer LINK: The European Physical Journal B - Abstract Volume 5 Issue 3 (1998) pp 325-335

The European Physical Journal B

ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)

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Abstract Volume 5 Issue 3 (1998) pp 325-335

Exact solution for a degenerate Anderson impurity in the $\mathsf{U \to \infty}$ limit embedded into a correlated host

P. Schlottmann (1) (a), A.A. Zvyagin (2)

(1) Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
(2) B.I. Verkin Institute for Low Temperature Physics and Engineering, Ukrainian National Academy of Sciences, 47 Lenin Avenue, Kharkov 310164, Ukraine

Received: 31 December 1997 / Accepted: 17 March 1998

Abstract: We consider the one-dimensional t-J model, which consists of electrons with spin S on a lattice with nearest neighbor hopping t constrained by the excluded multiple occupancy of the lattice sites and spin-exchange J between neighboring sites. The model is integrable at the supersymmetric point, J = t. Without spoiling the integrability we introduce an Anderson-like impurity of spin S (degenerate Anderson model in the $U \to \infty$ limit), which interacts with the correlated conduction states of the host. The lattice model is defined by the scattering matrices via the Quantum Inverse Scattering Method. We discuss the general form of the interaction Hamiltonian between the impurity and the itinerant electrons on the lattice and explicitly construct it in the continuum limit. The discrete Bethe ansatz equations diagonalizing the host with impurity are derived, and the thermodynamic Bethe ansatz equations are obtained using the string hypothesis for arbitrary band filling as a function of temperature and external magnetic field. The properties of the impurity depend on one coupling parameter related to the Kondo exchange coupling. The impurity can localize up to one itinerant electron and has in general mixed valent properties. Groundstate properties of the impurity, such as the energy, valence, magnetic susceptibility and the specific heat $\gamma$ coefficient, are discussed. In the integer valent limit the model reduces to a Coqblin-Schrieffer impurity.

PACS. 75.20.Hr Local moment in compounds and alloys; Kondo effect, valence fluctuations, heavy fermions - 75.30.Mb Valence fluctuation, Kondo lattice, and heavy-fermion phenomena - 71.27.+a Strongly correlated electron systems; heavy fermions

(a) email: schlottm@phy.fsu.edu

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