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Phys. Rev. Lett. 102, 166806 (2009) [4 pages]

Tunable Pseudogap Kondo Effect and Quantum Phase Transitions in Aharonov-Bohm Interferometers

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Luis G. G. V. Dias da Silva1,*, Nancy Sandler2, Pascal Simon3,4, Kevin Ingersent5, and Sergio E. Ulloa2
1Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA and Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
2Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701-2979, USA
3Laboratoire de Physique et Modélisation des Milieux Condensés, CNRS et Université Joseph Fourier, 38042 Grenoble, France
4Laboratoire de Physique des Solides, CNRS UMR-8502, Université Paris Sud, 91405 Orsay Cedex, France
5Department of Physics, University of Florida, P.O. Box 118440, Gainesville, Florida 32611-8440, USA

Received 11 January 2009; published 24 April 2009

We study two quantum dots embedded in the arms of an Aharonov-Bohm ring threaded by a magnetic flux. This system can be described by an effective one-impurity Anderson model with an energy- and flux-dependent density of states. For specific values of the flux, this density of states vanishes at the Fermi energy, yielding a controlled realization of the pseudogap Kondo effect. The conductance and transmission phase shifts reflect a nontrivial interplay between wave interference and interactions, providing clear signatures of quantum phase transitions between Kondo and non-Kondo ground states.

© 2009 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.102.166806
DOI:
10.1103/PhysRevLett.102.166806
PACS:
73.21.La, 65.80.+n, 72.10.Fk

*diasdasilval@ornl.gov

 
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