Measuring electron spin flip-flops through nuclear spin echo decays

Evan S. Petersen, A. M. Tyryshkin, K. M. Itoh, H. Riemann, N. V. Abrosimov, P. Becker, H. J. Pohl, M. L.W. Thewalt, S. A. Lyon

Research output: Contribution to journalArticlepeer-review


We use the nuclear spin coherence of 31P donors in 28Si to determine flip-flop rates of donor electron spins. Isotopically purified 28Si crystals minimize the number of 29Si flip-flops, and measurements at 1.7 K suppress electron spin relaxation. The crystals have donor concentrations ranging from 1.2 × 1014 to 3.3 × 1015 P/cm3, allowing us to detect how electron flip-flop rates change with donor density. We also simulate how electron spin flip-flops can cause nuclear spin decoherence. We find that when these flip-flops are the primary cause of decoherence, Hahn echo decays have a stretched exponential form. For our two higher donor density crystals (> 1015 P/cm3), there is excellent agreement between simulations and experiments. In lower density crystals (< 1015 P/cm3), there is no longer agreement between simulations and experiments, suggesting a different, unknown mechanism is limiting nuclear spin coherence. The nuclear spin coherence in the lowest density crystal (1.2 × 1014 P/cm3) allows us to place upper bounds on the magnitude of noise sources in bulk crystals such as electric field fluctuations that may degrade silicon quantum devices.

Original languageEnglish
JournalUnknown Journal
Publication statusPublished - 2017 Sep 8

ASJC Scopus subject areas

  • General

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