In the archetypal monolayer semiconductor ${\mathrm{WSe}}_2$, 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 ${\mathrm{WSe}}_2$ 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 distinguishable spin and valley quantum numbers. In addition, we explain the relations between dark trions and satellite optical transitions of hexcitons in the photoluminescence spectrum.

中文翻译：

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单层WSe2 中的六体和八体激子态

在原型单层半导体中${\mathrm{WSe}}_2$，导带中自旋极化谷（低能袋）的不同排序不仅可以研究简单的中性激子和带电激子（即三重离子），还可以研究更复杂的多体状态，这些状态在更高电子密度。我们讨论富电子的磁光测量${\mathrm{WSe}}_2$单层，并将高电子掺杂时出现的谱线解释为六体激子态（“六激子”）和八体激子态（“氧激子”）的光学跃迁。当光激发电子-空穴对与多个费米海同时相互作用时，就会出现这些多体态，每个费米海都有可区分的自旋和谷量子数。此外，我们还解释了光致发光光谱中暗三重子与六核子的卫星光学跃迁之间的关系。