The interactions between charges and excitons involve complex many-body interactions at high densities. The exciton-polaron model has been adopted to understand the Fermi sea screening of charged excitons in monolayer transition metal dichalcogenides. The results provide good agreement with absorption measurements, which are dominated by dilute bright exciton responses. Here we investigate the Fermi sea dressing of spin-forbidden dark excitons in monolayer WSe₂. With a Zeeman field, the valley-polarized dark excitons show distinct p-doping dependence in photoluminescence when the carriers reach a critical density. This density can be interpreted as the onset of strongly modified Fermi sea interactions and shifts with increasing exciton density. Through valley-selective excitation and dynamics measurements, we also infer an intervalley coupling between the dark trions and exciton-polarons mediated by the many-body interactions. Our results reveal the evolution of Fermi sea screening with increasing exciton density and the impacts of polaron-polaron interactions, which lay the foundation for understanding electronic correlations and many-body interactions in 2D systems.

电荷和激子之间的相互作用涉及高密度下复杂的多体相互作用。采用激子-极化子模型来理解单层过渡金属二硫属化物中带电激子的费米海屏蔽。结果与吸收测量结果非常吻合，吸收测量主要是稀亮激子响应。_{在这里，我们研究了单层 WSe 2}中自旋禁止暗激子的费米海选矿。利用塞曼场，当载流子达到临界密度时，谷偏振暗激子在光致发光中表现出明显的 p 掺杂依赖性。该密度可以解释为强烈修改的费米海相互作用的开始，并随着激子密度的增加而变化。通过谷选择性激发和动力学测量，我们还推断出暗三重子和激子极化子之间由多体相互作用介导的层间耦合。我们的结果揭示了费米海屏蔽随激子密度增加的演变以及极化子-极化子相互作用的影响，这为理解二维系统中的电子关联和多体相互作用奠定了基础。