Emerging photoluminescence from the dark-exciton phonon replica in monolayer WSe2
Abstract
Tungsten-based monolayer transition metal dichalcogenides host a long-lived “dark” exciton, an electron-hole pair in a spin-triplet configuration. The long lifetime and unique spin properties of the dark exciton provide exciting opportunities to explore light-matter interactions beyond electric dipole transitions. Here we demonstrate that the coupling of the dark exciton and an optically silent chiral phonon enables the intrinsic photoluminescence of the dark-exciton replica in monolayer WSe2. Gate and magnetic-field dependent PL measurements unveil a circularly-polarized replica peak located below the dark exciton by 21.6 meV, equal to E″ phonon energy from Se vibrations. First-principles calculations show that the exciton-phonon interaction selectively couples the spin-forbidden dark exciton to the intravalley spin-allowed bright exciton, permitting the simultaneous emission of a chiral phonon and a circularly-polarized photon. Our discovery and understanding of the phonon replica reveals a chirality dictated emission channel of the phonons and photons, unveiling a new route of manipulating valley-spin.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 06, 2019
- Source ID
- 10.1038/s41467-019-10477-6
Entities
People
- Chenhao Jin
- Dmitry Smirnov
- Kenji Watanabe
- Mark Blei
- Sefaattin Tongay
- Shiyuan Gao
- Su-Fei Shi
- Takashi Taniguchi
- Tianhui Ren
- Tianmeng Wang
- Ting Cao
- Yang Li
- Yuze Meng
- Zhen Lian
- Zhengguang Lu
- Zhipeng Li
Organizations
- Air Force Office of Scientific Research