Figure 5. Ab initio Floquet k.p classification of photo-induced band inversions in WS₂.

(a) Starting from a 185-band first-principles description of the K point, multi-photon processes involving deep core levels and higher-energy as well as local dipole transitions can be taken into account exactly. (b) Recomputing the effective Floquet k.p two-band model of the photo-induced band inversion recovers a phase diagram that is qualitatively similar to the three-band tight-binding description (Fig. 4d), suggesting that the photo-induction of one or two chiral edge modes for appropriate tuning of the pump laser is robust to multi-photon processes at weak pump fields. Strong pump-field deviations indicate a non-trivial admixing of higher-energy bands.