Figure 5: Zoom on theoretical spectrum near B_empty.

(a) Zoom on theoretical evolution of the Landau levels and the Fermi energy of Fig. 2a (B||Binary). This is where the two lowest electron Landau levels and the penultimate hole Landau level cross the Fermi level. (b) The difference of energy between electron and hole Landau levels and the Fermi energy. Bound excitonic states can be formed if the Coulomb attraction between electrons and holes exceed the sum of kinetic energy of electrons and holes. Note that here the calculations assume =10⁻⁸. In principle, the Zeeman energy of holes becomes zero when the field is perpendicular to the trigonal axis²⁸ (see more description in Supplementary Note 1) and therefore =0.