Extended Data Fig. 6: Determination of the accuracy of the twist-angle measurement.
From: Mapping the twist-angle disorder and Landau levels in magic-angle graphene
a, Traces of \(-{B}_{z}^{{\rm{ac}}}\) versus Vbg in device A (from Fig. 1f) acquired with a step size ΔVbg = 4.7 mV and an r.m.s. \({V}_{{\rm{bg}}}^{{\rm{ac}}}\) = 15 mV. The positions of the \({V}_{{\rm{bg}}}^{N=-3}\) and \({V}_{{\rm{bg}}}^{N=-4}\) peaks can be determined to an accuracy better than ±ΔVbg (one step size), corresponding to a relative θ accuracy of δθ = ±0.0002°. b, As in a, taken from Supplementary Video 1 at a pixel position (x, y) = (2.53 μm, 5.9 μm) with step size ΔVbg = 40 mV and an r.m.s. \({V}_{{\rm{bg}}}^{{\rm{ac}}}\) = 35 mV, resulting in a relative θ accuracy of δθ = ±0.002° in the imaging mode. The larger \({B}_{z}^{{\rm{ac}}}\) signal and the broader IT peaks in b compared to a are due to larger \({V}_{{\rm{bg}}}^{{\rm{ac}}}\) excitation (see Methods section ‘Measurement parameters’).
