Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 22: Transport: Poster Session

TT 22.13: Poster

Mittwoch, 27. Februar 2008, 14:00–18:00, Poster B

Tunable transmission via quantum state evolution in oval quantum dots — •Daniel Buchholz¹, Panagiotis Drouvelis³, and Peter Schmelcher^1,2 — ¹Theoretische Chemie, Universität Heidelberg, INF 229, 69120 Heidelberg, Deutschland — ²Tyndall National Institute, Lee Maltings, Prospect Row, Cork, Ireland — ³Physikalisches Institut, Universität Heidelberg, Philosophenweg 12, 69120 Heidelberg, Deutschland

We explore the quantum transmission through open oval shaped quantum dots. The transmission spectra show periodic resonances and, depending on the geometry parameter, a strong suppression of the transmission for low energies. Applying a weak perpendicular magnetic field changes this situation drastically and introduces a large conductance. We identify the underlying mechanisms being partially due to the specific shape of the oval that causes a systematic decoupling of a substantial number of states from the leads. Importantly a pairwise destructive interference of the transmitting states is encountered thereby leading to the complete conductance suppression. Coupling properties and interferences can be tuned via a weak magnetic field. These properties are robust with respect to the presence of disorder in the quantum dot.