@article{842a52f300fd41c6a7885215dd2798e0,
title = "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.",
author = "Zhipeng Li and Tianmeng Wang and Chenhao Jin and Zhengguang Lu and Zhen Lian and Yuze Meng and Mark Blei and Shiyuan Gao and Takashi Taniguchi and Kenji Watanabe and Tianhui Ren and Sefaattin Tongay and Li Yang and Dmitry Smirnov and Ting Cao and Shi, {Su Fei}",
note = "Funding Information: We thank Prof. Feng Wang, Prof. Steven G. Louie and Prof. Ronald Hedden for helpful discussions. This work is supported by AFOSR through grant FA9550-18-1-0312. The device fabrication was supported by Micro and Nanofabrication Clean Room (MNCR) at Rensselaer Polytechnic Institute (RPI). Z. Li acknowledges support from the Shanghai Sailing Program (19YF1425200). S.T. acknowledges support from NSF DMR-1552220 and DMR 1838443. C.J. acknowledges support from a Kavli Postdoctoral Fellowship. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan and the CREST (JPMJCR15F3), JST. T.C. acknowledges support from a GLAM postdoctoral fellowship provided by the Stanford University and a start-up fund provided by the University of Washington. S.-F.S. and Z. Lian also acknowledge support from the NY State Empire State Development{\textquoteright}s Division of Science, Technology, and Innovation (NYSTAR) through Focus Center-NY–RPI Contract C150117. Publisher Copyright: {\textcopyright} 2019, The Author(s).",
year = "2019",
month = dec,
day = "1",
doi = "10.1038/s41467-019-10477-6",
language = "English (US)",
volume = "10",
journal = "Nature Communications",
issn = "2041-1723",
publisher = "Nature Publishing Group",
number = "1",
}