Fig. 4: Charge noise measurements.
a Charge noise power spectral density Sϵ measured on a flank of a Coulomb peak and extracted using the lever arm of the corresponding Coulomb diamond. The black line is a fit to the function, which is the sum of a power law and a Lorentzian. b Experimental scatter plots of charge noise at 1 Hz (\({S}_{\epsilon }^{1/2}(1\,\,{{{\rm{Hz}}}})\)) obtained by repeating charge noise spectrum measurements as in (a) for multiple devices and different electron occupancy. Data from the 6.9(5) nm quantum well (purple, 2 devices, 17 spectra) is compared to data from the 5.3(5) nm quantum well (green, 63 spectra, 5 devices, reported in ref. 18). We compare single-layer devices (diamonds) and multi-layer devices featuring overlapping gate geometry and micromagnets (circles). Dashed lines and shaded area denote the mean value and two standard deviations.
