Polarization analysis of excitons in monolayer and bilayer transition-metal dichalcogenides

The authors theoretically study optical transitions in transition-metal dichalcogenides. In particular, they explain the difference between the excitonic properties of monolayer MoSe₂ and WSe₂. Excitons in WSe₂ are thought to be bound to impurities. An alternative theory presented in this paper suggests that these excitons correspond to low-energy optical transitions. The authors also put forward an alternative explanation as to why the excitons in MoSe₂ have vanishing polarization. They attribute this phenomenon to polaron-induced Rabi oscillations between dark and bright excitons.