Coherent spin states in semiconductor quantum dots offer promise as electrically controllable quantum bits (qubits) with scalable fabrication. For few-electron quantum dots made from gallium arsenide (GaAs), fluctuating nuclear spins in the host lattice are the dominant source of spin decoherence. We report a method of preparing the nuclear spin environment that suppresses the relevant component of nuclear spin fluctuations below its equilibrium value by a factor of ~ 70, extending the inhomogeneous dephasing time for the two-electron spin state beyond 1 microsecond. The nuclear state can be readily prepared by electrical gate manipulation and persists for > 10 seconds.
@article{arxiv.0807.1445,
title = {Suppressing Spin Qubit Dephasing by Nuclear State Preparation},
author = {D. J. Reilly and J. M. Taylor and J. R. Petta and C. M. Marcus and M. P. Hanson and A. C. Gossard},
journal= {arXiv preprint arXiv:0807.1445},
year = {2013}
}
Comments
Supporting material available at http://marcuslab.harvard.edu/papers.shtml