The interplay of the nonequivalent corners in the Brillouin zone of transition metal dichalcogenides (TMDCs) has been investigated extensively. While experimental and theoretical works contributed to a detailed understanding of the relaxation of selective optical excitations and the related relaxation rates, only limited microscopic descriptions of stationary experiments are available so far. Here we present microscopic calculations for the nonequilibrium steady state properties of excitons during continuous wave pumping exemplary for monolayer ${\mathrm{MoSe}}_2$. We find sharp features in photoluminescence excitation spectra and degree of polarization which result from phonon assisted excitonic transitions dominating over exciton recombination and intervalley exchange coupling.

• Received 10 January 2022
• Revised 1 June 2023
• Accepted 22 August 2023

DOI:https://doi.org/10.1103/PhysRevLett.131.146201