Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 35: Postersession Transport: Nanoelectronics, Quantum Coherence and Quantum Information, Fluctuations and Noise
TT 35.6: Poster
Mittwoch, 25. März 2009, 14:00–18:00, P1A
Nonequilibrium transport through a correlated quantum dot with magnetic impurity — •Daniel Becker1, Stephan Weiss2, Michael Thorwart3, and Daniela Pfannkuche1 — 1I. Institute for Theoretical Physics, University of Hamburg, D-20355 Hamburg, Germany — 2Niels Bohr Instituttet, Nano-Science Centret, Universitetsparken 5, DK-2100 Copenhagen, Denmark — 3FRIAS, Albert-Ludwigs-Universität Freiburg, Albertstr.19, 79104 Freiburg, Germany
The deterministic, non-perturbative scheme of iterative summation of path integrals (ISPI)[1] is adopted to a single-level quantum dot with one quantum spin-1/2 magnetic impurity interacting with the dot-electron spins. For two electrons on the dot, Coulomb interaction is taken into account. A generating function is obtained to calculate the dc tunneling current at finite bias voltages and the orientation of the impurity spin. This real-time path integral extends over all paths of (i) the magnetic impurity spin and of (ii) Ising-like fluctuating spin fields, which are introduced to decouple the interacting dot-electrons. With the use of the ISPI scheme, the sum over all these paths can be carried out numerically, while exactly accounting for all lead-induced self-energies within a sufficiently long, but finite coherence time. This allows to study real-time nonequilibrium transport through the considered system in the case of strong electron-impurity interaction as well as strong coupling to the leads, even at low temperatures and for a wide range of bias voltages. In particular, the mutual influence between tunneling current and the impurity spin dynamics is of interest.
[1] S. Weiss et al., Phys. Rev. B 77, 195316 (2008)