Ultrafast dynamics in monolayer transition metal dichalcogenides: Interplay of dark excitons, phonons, and intervalley exchange

This is the authors' abstract. We don't add key points for this paper.

The authors present a microscopic explanation for the bleaching at the excitonic B transition in monolayers of transition metal dichalcogenides, based on the joint action of exchange coupling and phonon-mediated thermalization into dark exciton states. The paper shows how intra- and intervalley coupling on a femtosecond timescale governs the optical valley response of 2D semiconductors.