Fig. 5: GW-BSE results for optical absorption, exciton Zeeman splitting, and transition contributions.

a Mean exciton Zeeman splitting as a function of excitation energy. The colorcode on the line represents the absorption strength at each energy. b–d Electron-hole transitions contributing to excitons in the energy range associated with Q2, namely in the magenta shaded area in a. The electron bands (cD1 and cD2), as well as the hole bands (vD and VB) are illustrated in energetic order under the consideration of the lifted spin degeneracy at the \(K/{K}^{{\prime} }\)-points. e–g Electron-hole transitions contributing to excitons in the energy range associated with Q1, namely in the gray shaded area in a. The transitions are shown for three selective k-points, K (b, e), Γ (c, f), and \({K}^{{\prime} }\) (d, g).