Six-Body and Eight-Body Exciton States in Monolayer WSe2

In the archetypal monolayer semiconductor WSe2, the distinct ordering of spin-polarized valleys (low-energy pockets) in the conduction band allows for studies of not only simple neutral excitons and charged excitons (i.e., trions), but also more complex many-body states that are predicted at higher electron densities. We discuss magneto-optical measurements of electron-rich WSe2 monolayers and interpret the spectral lines that emerge at high electron doping as optical transitions of six-body exciton states ( hexcitons ) and eight-body exciton states ( oxcitons ). These many-body states emerge when a photoexcited electron-hole pair interacts simultaneously with multiple Fermi seas, each having distinguish-able spin and valley quantum numbers. In addition, we explain the relations between dark trions and satellite optical transitions of hexcitons in the photoluminescence spectrum.

Automated summary

In the monolayer semiconductor WSe2, magneto-optical measurements have revealed optical transitions of six-body exciton states (hexcitons) and eight-body exciton states (oxcitons) at high electron doping levels, where photoexcited electron-hole pairs interact with multiple Fermi seas. These many-body states involve distinguishable spin and valley quantum numbers and are related to dark trions and satellite optical transitions of hexcitons in the photoluminescence spectrum.