Fig. 2

Excitons in bilayer WSe₂. a Schematic single-particle band diagram of the conduction and the valence bands of bilayer WSe₂ along high-symmetry lines of the hexagonal Brillouin zone shown on the right. Zero-momentum spin-bright (X) and spin-dark (D) excitons are formed in the K valley by electrons from spin-up and spin-down conduction sub-bands indicated in black and gray, respectively, paired with a spin-up valence band empty state. Momentum-indirect excitons with electrons and unoccupied states in dissimilar valleys are indicated by dashed ellipses. b Calculated dispersions of lowest-energy exciton manifolds in bilayer WSe₂ with energy minima given in eV with respect to the bright exciton X