The elementary optical excitations in two-dimensional semiconductors hosting itinerant electrons are attractive and repulsive polarons—excitons that are dynamically screened by electrons. Exciton polarons have hitherto been studied in translationally invariant degenerate Fermi systems. Here, we show that periodic distribution of electrons breaks the excitonic translational invariance and leads to a direct optical signature in the exciton-polaron spectrum. Specifically, we demonstrate that new optical resonances appear due to spatially modulated interactions between excitons and electrons in an incompressible Mott-like correlated state. Our observations demonstrate that resonant optical spectroscopy provides an invaluable tool for studying strongly correlated states, such as Wigner crystals and density waves, where exciton-electron interactions are modified by the emergence of charge order.

中文翻译：

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类似于Mott的相关绝缘子状态下的周期性电荷分布的光学特征

包含流动电子的二维半导体中的基本光学激发是有吸引力的和排斥的极化子-被电子动态屏蔽的激子。迄今为止，激子极化子已在翻译不变的简并费米系统中进行了研究。在这里，我们表明电子的周期性分布打破了激子的平移不变性，并导致激子-极化子谱中的直接光学特征。具体而言，我们证明了由于不可压缩的Mott状相关态中激子和电子之间的空间调制相互作用，出现了新的光学共振。我们的观察结果表明，共振光谱法为研究强相关态（例如维格纳晶体和密度波）提供了宝贵的工具，