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arXiv 2312.00985cond-mat.mes-hallcond-mat.quant-gas
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暗激子介质中的极化子极化激元准粒子

Polaronic polariton quasiparticles in a dark excitonic medium

Kenneth Choo, Olivier Bleu, Jesper Levinsen, Meera M. Parish

AI总结:

本文研究了暗激子介质对激子极化激元的修饰作用,发现暗激子通过密度涨落形成相干的极化子状准粒子,并利用多体格林函数方法揭示了光-物质耦合减弱的极化子机制及双激子极化激元的产生,为二维半导体极化激元实验提供了理论解释。

摘要:

激子极化激元是激子(束缚电子-空穴对)和腔光子的杂化粒子,因在较高温度下展现玻色-爱因斯坦凝聚及其他相干现象而闻名。然而,它们在半导体微腔中的形成往往伴随着光学暗激子态非相干池的出现,这些暗态可通过极化激元的物质组分与其发生相互作用。在此,我们证明这种暗激子介质的存在能够通过密度涨落来“修饰”极化激元,从而形成相干的极化子状准粒子,从根本上改变了它们的特性。我们采用多体格林函数方法,该方法自然地包含了超越应用于该系统的标准平均场理论的关联效应。随着激子密度的增加,我们发现光-物质耦合的减弱源于极化子修饰云,而非激子中费米子组分诱导的任何饱和效应。特别是,当极化激元的自旋与激子介质的自旋相反时,我们观察到了最强的效应。在这种情况下,与光的耦合产生了额外的极化子准粒子——双激子极化激元,它是由于极化激元 Feshbach 共振的暗激子对应体而出现的。我们的结果可以解释最近关于二维半导体中极化激元相互作用的实验,并有可能为定制激子极化激元的特性及其关联提供一条途径。

英文摘要:

Exciton polaritons are hybrid particles of excitons (bound electron-hole pairs) and cavity photons, which are renowned for displaying Bose Einstein condensation and other coherent phenomena at elevated temperatures. However, their formation in semiconductor microcavities is often accompanied by the appearance of an incoherent bath of optically dark excitonic states that can interact with polaritons via their matter component. Here we show that the presence of such a dark excitonic medium can "dress" polaritons with density fluctuations to form coherent polaron-like quasiparticles, thus fundamentally modifying their character. We employ a many-body Green's function approach that naturally incorporates correlations beyond the standard mean-field theories applied to this system. With increasing exciton density, we find a reduction in the light-matter coupling that arises from the polaronic dressing cloud rather than any saturation induced by the fermionic constituents of the exciton. In particular, we observe the strongest effects when the spin of the polaritons is opposite that of the excitonic medium. In this case, the coupling to light generates an additional polaron quasiparticle - the biexciton polariton - which emerges due to the dark-exciton counterpart of a polariton Feshbach resonance. Our results can explain recent experiments on polariton interactions in two-dimensional semiconductors and potentially provide a route to tailoring the properties of exciton polaritons and their correlations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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