Figure 3
From: Single-particle properties of topological Wannier excitons in bismuth chalcogenide nanosheets
Behavior of the spin-orbit-parity pseudospin around the origin of momentum. As the polar angle \(\phi _{\varvec{Q}}\) varies from 0 to \(2 \pi\), the pseudospin \(\varvec{\sigma }\) of the states \(| \varvec{Q}; 2_{+} \rangle\) (left) and \(| \varvec{Q}; 2_{-} \rangle\) (right) winds around twice, as its orientation is coupled to that of the total exciton momentum.
