Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 6: Postersession Correlated Electrons: (General) Theory, Low-Dimensional Systems, Kondo Physics, Heavy Fermions, Quantum-Critical Phenomena
TT 6.44: Poster
Montag, 23. März 2009, 13:00–16:45, P1A
The chaotic Kondo box: mean-field approach — •Sebastien Burdin1, Rainer Bedrich2, and Martina Hentschel2 — 1Institute of Theoretical Physics, Cologne University — 2Max Planck Institute for the Physics of Complex Systems, Dresden
We study the low temperature physical properties of a mesoscopic bath of electrons (E.g., a big quantum dot), coupled to a local Kondo impurity (E.g., a small quantum dot, or a magnetic ion). Here, a crucial difference with the Kondo effect occuring in a bulk material results from a finite mean level spacing. This low energy scale can generate deviations from the universal behavior which would be expected for a bulk system. Using a mean-field approximation for the Kondo interaction, we consider as a first step a "clean system", where the non-interacting energy levels are characterized by a constant distribution. Then, a more realistic situation is considered, for which the energy levels are distributed randomly. This is realized within the random matrix theory. In both cases, we study the local magnetic susceptibility, the conductance, and the local density of electronic states as a function of the temperature, the mean level spacing, the Kondo coupling, and the number of electrons on the dot.