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Phys. Rev. B 73, 195329 (2006) [8 pages]

Breakdown of phase rigidity and variations of the Fano effect in closed Aharonov-Bohm interferometers

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Amnon Aharony1,2,3, Ora Entin-Wohlman1,2,3, Tomohiro Otsuka1, Shingo Katsumoto1,*, Hisashi Aikawa1,†, and Kensuke Kobayashi1,‡
1Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8581, Japan
2School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
3Physics Department, Ben Gurion University, Beer Sheva 84105, Israel

Received 16 December 2005; revised 16 February 2006; published 30 May 2006

Although the conductance of a closed Aharonov-Bohm interferometer, with a quantum dot on one branch, obeys the Onsager symmetry under magnetic field reversal, it needs not be a periodic function of this field: The conductance maxima move with both the field and the gate voltage on the dot, in an apparent breakdown of “phase rigidity.” These experimental findings are explained theoretically as resulting from multiple electronic paths around the interferometer ring. Data containing several Coulomb blockade peaks, whose shapes change with the magnetic flux, are fitted to a simple model, in which each resonant level on the dot couples to a different path around the ring.

© 2006 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevB.73.195329
DOI:
10.1103/PhysRevB.73.195329
PACS:
73.21.La, 72.15.Qm, 73.23.Hk, 85.35.−p

*Email address: kats@issp.u-tokyo.ac.jp

Present address: Toshiba Corporation, Research and Development Center, 1, Komukai Toshibacho, Saiwai-ku, Kawasaki-shi, 212-8582 Kanagawa, Japan.

Present address: Institute of Chemical Research, Kyoto University, Gokasho Uji, Kyoto 611-0011, Japan.