Longitudinal resistance {R}_{{xx}} versus carrier density n (top axis) and magnetic field {B}mathrm{a} at temperature T = 300 mK shown on a logarithmic scale. Two Landau fans emanate from the CNP: a steep fan originating from the FB LLs and a shallow fan originating from the Dirac LLs (Extended Data Fig. 1a and Supplementary Information Section I ). Dashed blue lines follow the {R}_{{xx}} minima labelled by their Chern number C , defined by the slope. The blue circle marks where the first Dirac LL, N D = 1, crosses the top of the FB.
