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Signatures of moiré-trapped valley excitons in MoSe2/WSe2 heterobilayers

Author

Listed:
  • Kyle L. Seyler

    (University of Washington)

  • Pasqual Rivera

    (University of Washington)

  • Hongyi Yu

    (University of Hong Kong)

  • Nathan P. Wilson

    (University of Washington)

  • Essance L. Ray

    (University of Washington)

  • David G. Mandrus

    (Oak Ridge National Laboratory
    University of Tennessee
    University of Tennessee)

  • Jiaqiang Yan

    (Oak Ridge National Laboratory
    University of Tennessee)

  • Wang Yao

    (University of Hong Kong)

  • Xiaodong Xu

    (University of Washington
    University of Washington)

Abstract

The formation of moiré patterns in crystalline solids can be used to manipulate their electronic properties, which are fundamentally influenced by periodic potential landscapes. In two-dimensional materials, a moiré pattern with a superlattice potential can be formed by vertically stacking two layered materials with a twist and/or a difference in lattice constant. This approach has led to electronic phenomena including the fractal quantum Hall effect1–3, tunable Mott insulators4,5 and unconventional superconductivity6. In addition, theory predicts that notable effects on optical excitations could result from a moiré potential in two-dimensional valley semiconductors7–9, but these signatures have not been detected experimentally. Here we report experimental evidence of interlayer valley excitons trapped in a moiré potential in molybdenum diselenide (MoSe2)/tungsten diselenide (WSe2) heterobilayers. At low temperatures, we observe photoluminescence close to the free interlayer exciton energy but with linewidths over one hundred times narrower (around 100 microelectronvolts). The emitter g-factors are homogeneous across the same sample and take only two values, −15.9 and 6.7, in samples with approximate twist angles of 60 degrees and 0 degrees, respectively. The g-factors match those of the free interlayer exciton, which is determined by one of two possible valley-pairing configurations. At twist angles of approximately 20 degrees the emitters become two orders of magnitude dimmer; however, they possess the same g-factor as the heterobilayer at a twist angle of approximately 60 degrees. This is consistent with the umklapp recombination of interlayer excitons near the commensurate 21.8-degree twist angle7. The emitters exhibit strong circular polarization of the same helicity for a given twist angle, which suggests that the trapping potential retains three-fold rotational symmetry. Together with a characteristic dependence on power and excitation energy, these results suggest that the origin of the observed effects is interlayer excitons trapped in a smooth moiré potential with inherited valley-contrasting physics. This work presents opportunities to control two-dimensional moiré optics through variation of the twist angle.

Suggested Citation

  • Kyle L. Seyler & Pasqual Rivera & Hongyi Yu & Nathan P. Wilson & Essance L. Ray & David G. Mandrus & Jiaqiang Yan & Wang Yao & Xiaodong Xu, 2019. "Signatures of moiré-trapped valley excitons in MoSe2/WSe2 heterobilayers," Nature, Nature, vol. 567(7746), pages 66-70, March.
  • Handle: RePEc:nat:nature:v:567:y:2019:i:7746:d:10.1038_s41586-019-0957-1
    DOI: 10.1038/s41586-019-0957-1
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    Cited by:

    1. Mengqi Huang & Zeliang Sun & Gerald Yan & Hongchao Xie & Nishkarsh Agarwal & Gaihua Ye & Suk Hyun Sung & Hanyi Lu & Jingcheng Zhou & Shaohua Yan & Shangjie Tian & Hechang Lei & Robert Hovden & Rui He , 2023. "Revealing intrinsic domains and fluctuations of moiré magnetism by a wide-field quantum microscope," Nature Communications, Nature, vol. 14(1), pages 1-7, December.
    2. Ruoming Peng & Adina Ripin & Yusen Ye & Jiayi Zhu & Changming Wu & Seokhyeong Lee & Huan Li & Takashi Taniguchi & Kenji Watanabe & Ting Cao & Xiaodong Xu & Mo Li, 2022. "Long-range transport of 2D excitons with acoustic waves," Nature Communications, Nature, vol. 13(1), pages 1-7, December.
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    7. Jinjae Kim & Jiwon Park & Hyojin Choi & Taeho Kim & Soonyoung Cha & Yewon Lee & Kenji Watanabe & Takashi Taniguchi & Jonghwan Kim & Moon-Ho Jo & Hyunyong Choi, 2024. "Correlation-driven nonequilibrium exciton site transition in a WSe2/WS2 moiré supercell," Nature Communications, Nature, vol. 15(1), pages 1-9, December.
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    9. Elena Blundo & Federico Tuzi & Salvatore Cianci & Marzia Cuccu & Katarzyna Olkowska-Pucko & Łucja Kipczak & Giorgio Contestabile & Antonio Miriametro & Marco Felici & Giorgio Pettinari & Takashi Tanig, 2024. "Localisation-to-delocalisation transition of moiré excitons in WSe2/MoSe2 heterostructures," Nature Communications, Nature, vol. 15(1), pages 1-11, December.
    10. Giacomo Mazza & Marco Gandolfi & Massimo Capone & Francesco Banfi & Claudio Giannetti, 2021. "Thermal dynamics and electronic temperature waves in layered correlated materials," Nature Communications, Nature, vol. 12(1), pages 1-11, December.
    11. Hulin Yao & Pengcheng Zheng & Shibin Zhang & Chuanjie Hu & Xiaoli Fang & Liping Zhang & Dan Ling & Huanyang Chen & Xin Ou, 2024. "Twist piezoelectricity: giant electromechanical coupling in magic-angle twisted bilayer LiNbO3," Nature Communications, Nature, vol. 15(1), pages 1-8, December.
    12. N. Fang & Y. R. Chang & S. Fujii & D. Yamashita & M. Maruyama & Y. Gao & C. F. Fong & D. Kozawa & K. Otsuka & K. Nagashio & S. Okada & Y. K. Kato, 2024. "Room-temperature quantum emission from interface excitons in mixed-dimensional heterostructures," Nature Communications, Nature, vol. 15(1), pages 1-8, December.
    13. Veronica R. Policht & Henry Mittenzwey & Oleg Dogadov & Manuel Katzer & Andrea Villa & Qiuyang Li & Benjamin Kaiser & Aaron M. Ross & Francesco Scotognella & Xiaoyang Zhu & Andreas Knorr & Malte Selig, 2023. "Time-domain observation of interlayer exciton formation and thermalization in a MoSe2/WSe2 heterostructure," Nature Communications, Nature, vol. 14(1), pages 1-9, December.
    14. Meng Zhao & Zhongjie Wang & Lu Liu & Chunzheng Wang & Cheng-Yen Liu & Fang Yang & Hua Wu & Chunlei Gao, 2024. "Atomic-scale visualization of the interlayer Rydberg exciton complex in moiré heterostructures," Nature Communications, Nature, vol. 15(1), pages 1-10, December.
    15. Fateme Mahdikhanysarvejahany & Daniel N. Shanks & Matthew Klein & Qian Wang & Michael R. Koehler & David G. Mandrus & Takashi Taniguchi & Kenji Watanabe & Oliver L. A. Monti & Brian J. LeRoy & John R., 2022. "Localized interlayer excitons in MoSe2–WSe2 heterostructures without a moiré potential," Nature Communications, Nature, vol. 13(1), pages 1-6, December.
    16. Andrew Y. Joe & Andrés M. Mier Valdivia & Luis A. Jauregui & Kateryna Pistunova & Dapeng Ding & You Zhou & Giovanni Scuri & Kristiaan De Greve & Andrey Sushko & Bumho Kim & Takashi Taniguchi & Kenji W, 2024. "Controlled interlayer exciton ionization in an electrostatic trap in atomically thin heterostructures," Nature Communications, Nature, vol. 15(1), pages 1-8, December.
    17. Hongbing Cai & Abdullah Rasmita & Qinghai Tan & Jia-Min Lai & Ruihua He & Xiangbin Cai & Yan Zhao & Disheng Chen & Naizhou Wang & Zhao Mu & Zumeng Huang & Zhaowei Zhang & John J. H. Eng & Yuanda Liu &, 2023. "Interlayer donor-acceptor pair excitons in MoSe2/WSe2 moiré heterobilayer," Nature Communications, Nature, vol. 14(1), pages 1-7, December.
    18. Zhen Lian & Dongxue Chen & Yuze Meng & Xiaotong Chen & Ying Su & Rounak Banerjee & Takashi Taniguchi & Kenji Watanabe & Sefaattin Tongay & Chuanwei Zhang & Yong-Tao Cui & Su-Fei Shi, 2023. "Exciton Superposition across Moiré States in a Semiconducting Moiré Superlattice," Nature Communications, Nature, vol. 14(1), pages 1-7, December.
    19. Zhen Lian & Dongxue Chen & Lei Ma & Yuze Meng & Ying Su & Li Yan & Xiong Huang & Qiran Wu & Xinyue Chen & Mark Blei & Takashi Taniguchi & Kenji Watanabe & Sefaattin Tongay & Chuanwei Zhang & Yong-Tao , 2023. "Quadrupolar excitons and hybridized interlayer Mott insulator in a trilayer moiré superlattice," Nature Communications, Nature, vol. 14(1), pages 1-7, December.
    20. Zehua Hu & Tanjung Krisnanda & Antonio Fieramosca & Jiaxin Zhao & Qianlu Sun & Yuzhong Chen & Haiyun Liu & Yuan Luo & Rui Su & Junyong Wang & Kenji Watanabe & Takashi Taniguchi & Goki Eda & Xiao Rensh, 2024. "Energy transfer driven brightening of MoS2 by ultrafast polariton relaxation in microcavity MoS2/hBN/WS2 heterostructures," Nature Communications, Nature, vol. 15(1), pages 1-8, December.
    21. Xingdan Sun & Shihao Zhang & Zhiyong Liu & Honglei Zhu & Jinqiang Huang & Kai Yuan & Zhenhua Wang & Kenji Watanabe & Takashi Taniguchi & Xiaoxi Li & Mengjian Zhu & Jinhai Mao & Teng Yang & Jun Kang & , 2021. "Correlated states in doubly-aligned hBN/graphene/hBN heterostructures," Nature Communications, Nature, vol. 12(1), pages 1-8, December.
    22. Haonan Wang & Heejun Kim & Duanfei Dong & Keisuke Shinokita & Kenji Watanabe & Takashi Taniguchi & Kazunari Matsuda, 2024. "Quantum coherence and interference of a single moiré exciton in nano-fabricated twisted monolayer semiconductor heterobilayers," Nature Communications, Nature, vol. 15(1), pages 1-9, December.

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