Controlled dephasing in single-dot Aharonov-Bohm interferometers

V. Moldoveanu, M. Ţolea, and B. Tanatar
Phys. Rev. B 75, 045309 – Published 8 January 2007

Abstract

We study the Fano effect and the visibility of the Aharonov-Bohm oscillations for a mesoscopic interferometer with an embedded quantum dot in the presence of a nearby second dot. When the electron-electron interaction between the two dots is considered the nearby dot acts as a charge detector. We compute the currents through the interferometer and detector within the Keldysh formalism and the self-energy of the nonequilibrium Green’s functions is found up to the second order in the interaction strength. The current formula contains a correction to the Landauer-Büttiker formula. Its contribution to transport and dephasing is discussed. As the bias applied on the detector is increased, the amplitude of both the Fano resonance and Aharonov-Bohm oscillations are considerably reduced due to controlled dephasing. This result is explained by analyzing the behavior of the imaginary part of the interaction self-energy as a function of energy and bias. We emphasize as well the role of the ring-dot coupling. Our theoretical results are consistent with the experimental observation of Buks et al. [Nature 391, 871 (1998)].

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  • Received 3 April 2006

DOI:https://doi.org/10.1103/PhysRevB.75.045309

©2007 American Physical Society

Authors & Affiliations

V. Moldoveanu and M. Ţolea

  • National Institute of Materials Physics, P.O. Box MG-7, Bucharest-Magurele, Romania

B. Tanatar

  • Department of Physics, Bilkent University, Bilkent, 06800 Ankara, Turkey

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Issue

Vol. 75, Iss. 4 — 15 January 2007

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