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arXiv · 1008.2382

Electron spin decoherence in isotope-enriched silicon

Wayne M. Witzel·Malcolm S. Carroll·Andrea Morello·Lukasz Cywinski·S. Das Sarma
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Abstract

Silicon is promising for spin-based quantum computation because nuclear spins, a source of magnetic noise, may be eliminated through isotopic enrichment. Long spin decoherence times, $T_2$, have been measured in isotope-enriched silicon but come far short of the $T_2 = 2 T_1$ limit. The effect of nuclear spins on $T_2$ is well established. However, the effect of background electron spins from ever present residual phosphorus impurities in silicon can also produce significant decoherence. We study spin decoherence decay as a function of donor concentration, $^{29}$Si concentration, and temperature using cluster expansion techniques specifically adapted to the problem of a sparse dipolarly coupled electron spin bath. Our results agree with the existing experimental spin echo data in Si:P and establish the importance of background dopants as the ultimate decoherence mechanism in isotope-enriched silicon.

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Wayne M. Witzel, Malcolm S. Carroll, Andrea Morello, Lukasz Cywinski, S. Das Sarma. 2010-10-27. Electron spin decoherence in isotope-enriched silicon. https://doi.org/10.1103/physrevlett.105.187602

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