Regensburg 2002 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 17: Postersitzung II: Mesoskopische Systeme (1-19), Supraleiter: Theorie (20-26), Elektronenstruktur, Phononen, Tunneln, Ordnungsparameter (27-33), Schwere Fermionen, Kondo-Systeme (34-45)

TT 17.15: Poster

Mittwoch, 13. März 2002, 14:30–18:00, A

Transmission Phase Shift of a Quantum Dot with Kondo Correlations — •Michael Sindel, Laszlo Borda, and Jan von Delft — Sektion Physik und CeNS, Ludwig-Maximilians-Universität, Theresienstr. 37, 80333 München

Recently Ji et al. [1] measured the amplitude and the phase of the complex transmission amplitude of a Quantum Dot in the unitary limit. They observed that the phase of the transmission amplitude evolves linearly over a range of about 1.5 π when the Fermi energy is scanned through a pair of Coulomb blockade peaks in between which the dot exhibits Kondo correlations. Moreover, the phase in the Coulomb blockade peak, adjacent to the Kondo pair retained a memory of the Kondo correlation. Both, the large phase span of the transimission phase in the Kondo regime and the memory of the Kondo effect in the adjacent peaks is not in accord with the theoretical analyses by Gerland et al. [2] which was based on a single-level Anderson model.

We extend the latter analyses to the case of a multilevel Anderson model and also analyse the phase modulating effects of a nearby gate electrode. Finally we compare our results with experiment.

[1] Yang Ji et al, Transmission Phase of a Quantum Dot with Kondo Correlation near the Unitary Limit, cond-mat /0106469 v2 (2001)

[2] U. Gerland et al.,Transmission Phase Shift of a Quantum Dot with Kondo Correlations, PRL 84, 3710-3713, (2000)