Revealing broken valley symmetry of quantum emitters in WSe2 with chiral nanocavities

Longlong Yang; Yu Yuan; Bowen Fu; Jingnan Yang; Danjie Dai; Shushu Shi; Sai Yan; Rui Zhu; Xu Han; Hancong Li; Zhanchun Zuo; Can Wang; Yuan Huang; Kuijuan Jin; Qihuang Gong; Xiulai Xu

doi:10.1038/s41467-023-39972-7

Revealing broken valley symmetry of quantum emitters in WSe₂ with chiral nanocavities

Nat Commun. 2023 Jul 17;14(1):4265. doi: 10.1038/s41467-023-39972-7.

Authors

Longlong Yang^{1

2}, Yu Yuan^{1

2}, Bowen Fu³, Jingnan Yang³, Danjie Dai^{1

2}, Shushu Shi^{1

2}, Sai Yan^{1

2}, Rui Zhu^{1

2}, Xu Han⁴, Hancong Li³, Zhanchun Zuo^{1

2}, Can Wang^{5

6

7}, Yuan Huang⁸, Kuijuan Jin^{1

2

9}, Qihuang Gong^{3

10}, Xiulai Xu^{11

12}

Affiliations

¹ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
² CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
³ State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China.
⁴ Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, 100081, China.
⁵ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China. canwang@iphy.ac.cn.
⁶ CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China. canwang@iphy.ac.cn.
⁷ Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China. canwang@iphy.ac.cn.
⁸ Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, 100081, China. yhuang@bit.edu.cn.
⁹ Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China.
¹⁰ Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu, 226010, China.
¹¹ State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China. xlxu@pku.edu.cn.
¹² Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu, 226010, China. xlxu@pku.edu.cn.

Abstract

Single photon emission of quantum emitters (QEs) carrying internal degrees of freedom such as spin and angular momentum plays an important role in quantum optics. Recently, QEs in two-dimensional semiconductors have attracted great interest as promising quantum light sources. However, whether those QEs are characterized by the same valley physics as delocalized valley excitons is still under debate. Moreover, the potential applications of such QEs still need to be explored. Here we show experimental evidence of valley symmetry breaking for neutral QEs in WSe₂ monolayer by interacting with chiral plasmonic nanocavities. The anomalous magneto-optical behaviour of the coupled QEs suggests that the polarization state of emitted photon is modulated by the chiral nanocavity instead of the valley-dependent optical selection rules. Calculations of cavity quantum electrodynamics further show the absence of intrinsic valley polarization. The cavity-dependent circularly polarized single-photon output also offers a strategy for future applications in chiral quantum optics.