Intervalley electron-hole exchange interaction and impurity-assisted recombination of indirect excitons in WS2 and WSe2 monolayers

The variety of excitonic states in tungsten-based dichalcogenide monolayers stems from unique interplay between the spin and valley degrees of freedom. One of the exciton species is the indirect exciton (momentum or valley dark), which is responsible for a series of resonances when the monolayer is charge neutral. We investigate the short-range electron-hole exchange interaction of the indirect exciton, as well as its recombination mechanism mediated by impurities. The analysis provides thorough understanding of the energy and polarization of the zero-phonon indirect exciton resonance in the emission spectrum.

Automated summary

The variety of excitonic states in tungsten-based dichalcogenide monolayers originates from the unique interplay between spin and valley degrees of freedom. Among the exciton species, the indirect exciton (momentum or valley dark) is responsible for a series of resonances when the monolayer is charge neutral. In this study, we investigate the short-range electron-hole exchange interaction and the recombination mechanism mediated by impurities of the indirect exciton. The analysis provides a thorough understanding of the energy and polarization of the zero-phonon indirect exciton resonance in the emission spectrum.