Fig. 2: Orbital angular momentum and circular dichroism.
a Top view of the WSe2 monolayer and sketch of the first Brillouin zone. Upon rotating the crystal by 60°, the dominant orbital character at K (K\({}^{\prime}\)) reverse from the magnetic state d+2 (d−2) to d−2 (d+2), thus emulating the time-reversal operation. b Out-of-plane component of the orbital angular momentum Lz of the top valence band. The value of Lz is represented by the color as given by the color bar. c Calculated circular dichroism ICD(k, E) = ILCP(k, E) − IRCP(k, E) (LCP/RCP: left/right-hand circularly polarized) at binding energy E − EVBM = −0.215 eV for the orientation on the left-hand side of (a). Positive (negative) values are indicated by red (blue) color as given by the color bar above. The circular dichroism for the rotated crystal orientation is qualitatively similar. The probe pulse is coming from above.
