Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 46: Correlated Electrons: Quantum Impurities, Kondo Physics
TT 46.3: Vortrag
Freitag, 27. März 2009, 10:45–11:00, HSZ 301
Kondo effect in a mesoscopic interacting electron system — •Stefan Rotter1, Hakan Türeci2, Yoram Alhassid3, and Douglas Stone3 — 1TU--Vienna, Austria — 2ETH--Zürich, Switzerland — 3Yale, USA
We study the problem of a quantum dot with finite level spacing which is coupled anti-ferromagnetically to a Kondo spin (``Kondo box''). In particular, we investigate the influence of a ferromagnetic exchange interaction among the dot electrons as described by the ``Universal Hamiltonian''. The problem is solved numerically by diagonalizing the system Hamiltonian in a good-spin basis and analytically in the weak and strong Kondo coupling limits [1]. We provide an analytical solution for the effective strong coupling Hamiltonian which contains new interaction terms unknown from the conventional Kondo problem. The interplay between Kondo and ferromagnetic exchange correlations affects the ground-state spin of the system and can be probed with experimentally tunable parameters.
[1] S. Rotter, H. E. Türeci, Y. Alhassid, A. D. Stone, Phys. Rev. Lett. 100, 166601 (2008).