Phonon-exciton Interactions in WSe2 under a quantizing magnetic field
Zhipeng Li, Tianmeng Wang, Shengnan Miao, Yunmei Li, Zhenguang Lu, Chenhao Jin, Zhen Lian, Yuze Meng, Mark Blei, Takashi Taniguchi, Kenji Watanabe, Sefaattin Tongay, Wang Yao, Dmitry Smirnov, Chuanwei Zhang, Su‐Fei Shi
Abstract
Abstract 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 WSe 2 as an intriguing playground to study phonon-exciton interactions and their interplay with charge, spin, and valley.