Measuring electron spin flip-flops through nuclear spin echo decays
| Autor: | Petersen, Evan S., Tyryshkin, Alexei M., Itoh, Kohei M., Riemann, Helge, Abrosimov, Nikolai V., Becker, Peter, Pohl, Hans-Joachim, Thewalt, Mike L. W., Lyon, Stephen A. |
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| Rok vydání: | 2017 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | We use the nuclear spin coherence of $^{31}$P donors in $^{28}$Si to determine flip-flop rates of donor electron spins. Isotopically purified $^{28}$Si crystals minimize the number of $^{29}$Si flip-flops, and measurements at 1.7 K suppress electron spin relaxation. The crystals have donor concentrations ranging from $1.2\times10^{14}$ to $3.3\times10^{15}~\text{P/cm}^3$, 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 ($> 10^{15}~\text{P/cm}^3$), there is excellent agreement between simulations and experiments. In lower density crystals ($< 10^{15}~\text{P/cm}^3$), 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 ($1.2 \times 10^{14}~\text{P/cm}^3$) 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. Comment: 13 pages, 4 figures |
| Databáze: | arXiv |
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