Phonon-exciton Interactions in WSe2 under a quantizing magnetic field
Phonon-exciton Interactions in WSe2 under a quantizing magnetic field
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DOI：
10.1038/s41467-020-16934-x
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发表时间：
2020-06-19
影响因子：
16.6
通讯作者：
Shi, Su-Fei
中科院分区：
文献类型：
--
作者：
Li, Zhipeng;Wang, Tianmeng;Shi, Su-Fei
二维过渡金属二硫族化合物中的强多体相互作用为研究不同准粒子之间的相互作用提供了一个独特的平台，如突出的声子复制发射和修正的谷选择规则。一个大的面外磁场有望通过将激子量子化到离散朗道能级来改变激子-声子相互作用，这在很大程度上是未知的。在这里，我们观察了由声子-激子复合物产生的朗道能级，并在量子化磁场下直接探测了激子-声子相互作用。声子-激子相互作用提升了暗色子的朗道能级间跃迁选择规则，表现为与亮色子明显不同的朗道扇模式。这使我们能够通过实验提取空穴和电子的有效质量。朗道量子化的开始与谷-塞曼位移的显著增加相吻合，表明声子-激子相互作用有很强的多体效应。我们的工作证明单层WSe2是一个有趣的研究声子-激子相互作用及其与电荷，自旋和谷的相互作用的游乐场。
Strong many-body interaction in two-dimensional transitional metal dichalcogenides provides a unique platform to study the interplay between different quasiparticles, such as prominent phonon replica emission and modified valley-selection rules. A large out-of-plane magnetic field is expected to modify the exciton-phonon interactions by quantizing excitons into discrete Landau levels, which is largely unexplored. Here, we observe the Landau levels originating from phonon-exciton complexes and directly probe exciton-phonon interaction under a quantizing magnetic field. Phonon-exciton interaction lifts the inter-Landau-level transition selection rules for dark trions, manifested by a distinctively different Landau fan pattern compared to bright trions. This allows us to experimentally extract the effective mass of both holes and electrons. The onset of Landau quantization coincides with a significant increase of the valley-Zeeman shift, suggesting strong many-body effects on the phonon-exciton interaction. Our work demonstrates monolayer WSe2 as an intriguing playground to study phonon-exciton interactions and their interplay with charge, spin, and valley.