Tunable transmission via quantum state evolution in oval quantum dotsD. Buchholz1, P. Drouvelis2 and P. Schmelcher1, 3
1 Theoretische Chemie, University of Heidelberg - INF 229, 69120 Heidelberg, Germany
2 Tyndall National Institute, Lee Maltings - Prospect Row, Cork, Ireland
3 Physikalisches Institut, University of Heidelberg - Philosophenweg 12, 69120 Heidelberg, Germany
received 10 August 2007; accepted in final form 21 November 2007; published February 2008
published online 19 December 2007
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.
73.23.-b - Electronic transport in mesoscopic systems.
73.23.Ad - Ballistic transport.
75.47.Jn - Ballistic magnetoresistance.
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