Fig. 3: Properties of the weak transitions at D = 0.874 V/nm.

a Evolution of a typical branch of weak transitions between branch F and G in Fig. 1d. Spectra at 2.4–3.0 T (0.1 T step) are shifted horizontally to the center, and vertically by multiples of 0.1. Three peaks emerge gradually in the middle. b Fitting of the 2.8 T spectrum using seven Lorentzian peaks. The two side peaks in the weak transition branch correspond to (−9 → 7) and (−7 → 9). These Δ|N| = ± 2 transitions are allowed by the trigonal warping effect. The central peak corresponds to transition (−8 → 8) and its selection rule of Δ|N| = 0 is beyond an ideal single-particle picture. c Energy splitting between different pairs of peaks indicated by dashed lines in b. The splitting within branch F and G are plotted in pink (E₇₈) and green (E₈₉), respectively, whereas the sum of them is plotted in red (twice of the difference between electron and hole cyclotron energies). The splitting between (−9 → 7) and (−7 → 9) (E₇₉ plotted in blue) is very close to E₇₈ + E₈₉—corroborating our assignment of peaks in b.