Fig. 3
From: Scanning nuclear resonance imaging of a hyperfine-coupled quantum Hall system
NR-spectroscopic mapping. a Global nuclear resonance spectra captured at QH breakdown currents (indicated in the figure) at v = 1.02 and B = 8 T for sample B. The spectrum peaks show the Knight shift scaled by the upper horizontal axes within the minimum and maximum shifts Ks = 0−43.7 kHz (half the value of 2Ks), which were determined by fitting the reference data taken by pump-and-probe RD-NR measurements under unpolarised and fully polarised QH states (Supplementary Note 7). The curves are vertically offset for clarity. The vertical scale bar = 10 μV. b Optical micrograph of the Hall bar of sample B. The dashed square indicates a scanning area for NR spectroscopic mapping. The directions of the B-field and electron drift are also depicted. c, d NR Knight-shift (c) and intensity (d) images obtained by NR spectroscopic mapping (see Methods section); scale bar = 4 μm. The local Ks (c) is plotted when the intensity (d) is sufficiently large to deduce Ks at a cutoff intensity of 5.8 arb. units; otherwise, it is filled in with black. e Local NR spectra (circles) with fitting curves (red curves) at representative points marked by crosses in d, as indicated by i–v. The upper horizontal axis is scaled to half the value of 2Ks. Spectra taken at different points are offset vertically for clarity
