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Universal Recovery of the Energy-Level Degeneracy of Bright Excitons in InGaAs Quantum Dots without a Structure Symmetry

R. Trotta, E. Zallo, C. Ortix, P. Atkinson, J. D. Plumhof, J. van den Brink, A. Rastelli, and O. G. Schmidt
Phys. Rev. Lett. 109, 147401 – Published 1 October 2012
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Abstract

The lack of structural symmetry which usually characterizes semiconductor quantum dots lifts the energetic degeneracy of the bright excitonic states and hampers severely their use as high-fidelity sources of entangled photons. We demonstrate experimentally and theoretically that it is always possible to restore the excitonic degeneracy by the simultaneous application of large strain and electric fields. This is achieved by using one external perturbation to align the polarization of the exciton emission along the axis of the second perturbation, which then erases completely the energy splitting of the states. This result, which holds for any quantum dot structure, highlights the potential of combining complementary external fields to create artificial atoms meeting the stringent requirements posed by scalable semiconductor-based quantum technology.

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  • Received 7 June 2012

DOI:https://doi.org/10.1103/PhysRevLett.109.147401

© 2012 American Physical Society

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Quantum Dots Tuned for Entanglement

Published 1 October 2012

Researchers have applied a combination of an electric field and mechanical strain to a system of quantum dots in order to correct for asymmetries that usually prevent these semiconductor nanostructures from emitting entangled photons.

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Authors & Affiliations

R. Trotta1,2,*, E. Zallo1, C. Ortix3, P. Atkinson1,4, J. D. Plumhof1, J. van den Brink3, A. Rastelli1,2,†, and O. G. Schmidt1

  • 1Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden, Germany
  • 2Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstrasse 69, A-4040 Linz, Austria
  • 3Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden, Germany
  • 4Institut des NanoSciences des Paris, UPMC CNRS UMR 7588, 4 Place Jussieu Boite courier 840, Paris 75252 Cedex 05, France

  • *rinaldo.trotta@jku.at
  • armando.rastelli@jku.at

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Issue

Vol. 109, Iss. 14 — 5 October 2012

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