Tunable transmission via quantum state evolution in oval quantum dots

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: 21 November 2007

Abstract

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.