Fig. 3
From: Single-spin qubits in isotopically enriched silicon at low magnetic field
29Si-induced ESR frequency fluctuations. a Measurement of ESR frequencies of the two qubits over a time period of 140 min at 150 mT. There are significant fluctuations of the ESR frequencies of both qubits. Each point of measurement lasts about 2 min. b–g Histograms of ESR frequency fluctuations for both qubits at various magnetic fields. The distribution becomes more concentrated at higher magnetic field. h Red circles show the standard deviation of the fluctuation in ESR frequency of qubit QD1 plotted as a function of magnetic field, with error bars derived as in ref. 39. Each point is calculated based on a measurement that lasts 8 hours. The red line is a fit going as \(1/{B}_{z}^{0}\) at high field and saturating to 0.225 MHz at low field. Thin grey lines indicate simulations of 29Si nuclear spin-flip processes for 30 simulated samples with random nuclear placements. The error bars correspond to the standard error of the sample standard deviation estimated from the raw ESR jump data without any assumptions of the shape of the underlying distribution.
