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Ultrafast high-fidelity initialization of a quantum-dot spin qubit without magnetic fields

Jonathan D. Mar, Jeremy J. Baumberg, Xiulai Xu, Andrew C. Irvine, and David A. Williams
Phys. Rev. B 90, 241303(R) – Published 15 December 2014
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Abstract

We demonstrate the initialization of a single quantum-dot hole spin with high fidelity (lower bound >97%), on picosecond time scales, and without the need for magnetic fields. Using the initialization scheme based on rapid electric-field ionization of a resonantly excited exciton, this is achieved by employing a self-assembled quantum dot with a low conduction-to-valence band offset ratio, allowing control of the relative electron and hole tunneling rates over three orders of magnitude. This large difference in tunneling rates could permit spin-storage efficiencies >99.5% by fast-switching to a low electric-field condition. Our results may provide a practical route towards ultrafast high-fidelity initialization of individual quantum-dot hole spins for the implementation of quantum error correction in a scalable spin-based quantum computer.

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  • Received 13 June 2014

DOI:https://doi.org/10.1103/PhysRevB.90.241303

©2014 American Physical Society

Authors & Affiliations

Jonathan D. Mar1,2,*, Jeremy J. Baumberg2, Xiulai Xu1,†, Andrew C. Irvine3, and David A. Williams1

  • 1Hitachi Cambridge Laboratory, Cavendish Laboratory, Cambridge CB3 0HE, United Kingdom
  • 2NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
  • 3Microelectronics Research Centre, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom

  • *Author to whom correspondence should be addressed: jm585@cam.ac.uk
  • Present address: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.

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Issue

Vol. 90, Iss. 24 — 15 December 2014

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