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TT: Tiefe Temperaturen

TT 15: Korrelierte Elektronensysteme Theorie I

TT 15.6: Vortrag

Dienstag, 27. März 2001, 17:00–17:15, H

Magnetic impurity in a correlated conduction band — •Walter Hofstetter, Ralf Bulla, and Dieter Vollhardt — Theoretische Physik III, Universität Augsburg, 86135 Augsburg

We study the physics of a magnetic impurity with spin 1/2 embedded into a correlated metallic host [1]. Describing the band by a Hubbard Hamiltonian, the problem is analyzed by using dynamical mean-field theory in combination with Wilson’s numerical RG. We present results for the single–particle DOS and the dynamical impurity susceptibility at zero temperature. A strong enhancement of the Kondo scale due to band correlations is found. Moreover, the influence of an external magnetic field is studied by applying the recently developed DM–NRG [2]. Upon doping of the host, we find an increase of the Kondo scale, which reflects the reduced effective correlation strength away from half filling. Possible experimental verifications of this effect are discussed.

[1] W. Hofstetter, R. Bulla, and D. Vollhardt, Phys. Rev. Lett. 84,
4417 (2000).

[2] W. Hofstetter, Phys. Rev. Lett. 85, 1508 (2000).