Dresden 2006 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 26: Transport - Poster Session

TT 26.10: Poster

Mittwoch, 29. März 2006, 14:30–18:30, P1

Time-dependent Numerical Renormalization Group for Multi-Level Quantum Dots — •David Roosen and Walter Hofstetter — Theoretische Physik A, RWTH Aachen, D-52056 Aachen, Germany

During the last years Kondo phenomena have been realized in a controlled way in quantum dots with odd and even electron number [1]. Recent extensions of the Numerical Renormalization Group (NRG) [2] allow non-perturbative calculations of time-dependent phenomena in the Kondo regime. Here we investigate a two-level lateral quantum dot, taking into account Hund’s rule coupling. For this system it has been shown that a singlet-triplet Kondo effect occurs as a function of the level spacing [3]. Applying the time-dependent NRG algorithm of [2], we focus on the evolution of the system after a sudden change in the Hamiltonian, driving the quantum dot from the singlet to a triplet ground state.

[1] D. Goldhaber-Gordon et al., Nature 391, 156 (1998)

[2] F. Anders and A. Schiller, cond-mat/0505553

[3] W. Hofstetter and H. Schoeller, Phys. Rev. Lett. 88, 016803 (2002)