Identification of spin, valley and moiré quasi-angular momentum of interlayer excitons

Chenhao Jin, Emma C. Regan, Danqing Wang, M. Iqbal Bakti Utama, Chan Shan Yang, Jeffrey Cain, Ying Qin, Yuxia Shen, Zhiren Zheng, Kenji Watanabe, Takashi Taniguchi, Sefaattin Tongay, Alex Zettl, Feng Wang

Research output: Contribution to journalLetter

12 Scopus citations

Abstract

Moiré superlattices provide a powerful way to engineer the properties of electrons and excitons in two-dimensional van der Waals heterostructures1–8. The moiré effect can be especially strong for interlayer excitons, where electrons and holes reside in different layers and can be addressed separately. In particular, it was recently proposed that the moiré superlattice potential not only localizes interlayer exciton states at different superlattice positions, but also hosts an emerging moiré quasi-angular momentum (QAM) that periodically switches the optical selection rules for interlayer excitons at different moiré sites9,10. Here, we report the observation of multiple interlayer exciton states coexisting in a WSe2/WS2 moiré superlattice and unambiguously determine their spin, valley and moiré QAM through novel resonant optical pump–probe spectroscopy and photoluminescence excitation spectroscopy. We demonstrate that interlayer excitons localized at different moiré sites can exhibit opposite optical selection rules due to the spatially varying moiré QAM. Our observation reveals new opportunities to engineer interlayer exciton states and valley physics with moiré superlattices for optoelectronic and valleytronic applications.

Original languageEnglish (US)
Pages (from-to)1140-1144
Number of pages5
JournalNature Physics
Volume15
Issue number11
DOIs
StatePublished - Nov 1 2019

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Jin, C., Regan, E. C., Wang, D., Iqbal Bakti Utama, M., Yang, C. S., Cain, J., Qin, Y., Shen, Y., Zheng, Z., Watanabe, K., Taniguchi, T., Tongay, S., Zettl, A., & Wang, F. (2019). Identification of spin, valley and moiré quasi-angular momentum of interlayer excitons. Nature Physics, 15(11), 1140-1144. https://doi.org/10.1038/s41567-019-0631-4