Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 28: Transport - Poster Session
TT 28.54: Poster
Donnerstag, 29. März 2007, 14:00–17:45, Poster A
Mesoscopic to universal crossover of transmission phase of multi-level quantum dots — •Christoph Karrasch1, Theresa Hecht2, Yuval Oreg3, Jan von Delft2, and Volker Meden1 — 1Institut für Theoretische Physik, Göttingen, Germany — 2Physics Department, Ludwig-Maximilians-Universität, Munich, Germany — 3Department of Condensed Matter Physics, The Weizmann Institute of Science, Rehovot, Israel
Transmission phase α measurements [1] of many-electron quantum dots (small mean level spacing δ) revealed universal phase lapses by π between consecutive resonances. In contrast, for dots with only a few electrons (large δ), the appearance or not of a phase lapse depends on the dot parameters. We introduce a model of a multi-level quantum dot with local Coulomb correlations and arbitrary level-lead couplings [2]. Using the functional RG to tackle the two-particle interaction we reproduce the generic features of the experimentally observed behavior. The fRG results are backed up by NRG calculations.
[1] M. Avinun-Kalish, M. Heiblum, O. Zarchin, D. Mahalu, and V. Umansky, Nature 436, 529 (2005).
[2] C. Karrasch, T. Hecht, Y. Oreg, J. von Delft, and V. Meden (2006), cond-mat/0609191