Abstract
Van der Waals (vdW) materials have opened up many avenues for discovery through layer assembly, as epitomized by interlayer dipolar excitons that exhibit electrically tunable luminescence, lasing and exciton condensation. Extending interlayer excitons to more vdW layers, however, raises fundamental questions concerning coherence within excitons and coupling between moiré superlattices at multiple interfaces. Here, by assembling angle-aligned WSe2/WS2/WSe2 heterotrilayers, we demonstrate the emergence of quadrupolar excitons. We confirm the exciton’s quadrupolar nature by the decrease in its energy of 12 meV from coherent hole tunnelling between the two outer layers, its tunable static dipole moment under an external electric field and the reduced exciton–exciton interactions. At high exciton density, we also see signatures of a phase of oppositely aligned dipolar excitons, consistent with a staggered dipolar phase predicted to be driven by attractive dipolar interactions. Our demonstration paves the way for discovering emergent exciton orderings for three vdW layers and beyond.
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Source data are provided with this paper. All other datasets generated during and/or analysed during this study are available from the corresponding authors upon reasonable request.
References
Geim, A. K. & Grigorieva, I. V. Van der Waals heterostructures. Nature 499, 419–425 (2013).
Rivera, P. et al. Observation of long-lived interlayer excitons in monolayer MoSe2–WSe2 heterostructures. Nat. Commun. 6, 6242 (2015).
Jauregui, L. A. et al. Electrical control of interlayer exciton dynamics in atomically thin heterostructures. Science 366, 870–875 (2019).
Karni, O. et al. Infrared interlayer exciton emission in MoS2/WSe2 heterostructures. Phys. Rev. Lett. 123, 247402 (2019).
Seyler, K. L. et al. Signatures of moiré-trapped valley excitons in MoSe2/WSe2 heterobilayers. Nature 567, 66–70 (2019).
Tran, K. et al. Evidence for moiré excitons in van der Waals heterostructures. Nature 567, 71–75 (2019).
Jin, C. et al. Observation of moiré excitons in WSe2/WS2 heterostructure superlattices. Nature 567, 76–80 (2019).
Alexeev, E. M. et al. Resonantly hybridized excitons in moiré superlattices in van der Waals heterostructures. Nature 567, 81–86 (2019).
Park, J. M., Cao, Y., Watanabe, K., Taniguchi, T. & Jarillo-Herrero, P. Tunable strongly coupled superconductivity in magic-angle twisted trilayer graphene. Nature 590, 249–255 (2021).
Slobodkin, Y. et al. Quantum phase transitions of trilayer excitons in atomically thin heterostructures. Phys. Rev. Lett. 125, 255301 (2020).
Astrakharchik, G. E., Kurbakov, I. L., Sychev, D. V., Fedorov, A. K. & Lozovik, Y. E. Quantum phase transition of a two-dimensional quadrupolar system. Phys. Rev. B 103, L140101 (2021).
Tong, Q., Chen, M., Xiao, F., Yu, H. & Yao, W. Interferences of electrostatic moiré potentials and bichromatic superlattices of electrons and excitons in transition metal dichalcogenides. 2D Mater. 8, 025007 (2020).
Choi, C. et al. Enhanced interlayer neutral excitons and trions in trilayer van der Waals heterostructures. npj 2D Mater. Appl. 2, 30 (2018).
Baranowski, M. et al. Probing the interlayer exciton physics in a MoS2/MoSe2/MoS2 van der Waals heterostructure. Nano Lett. 17, 6360–6365 (2017).
Ceballos, F., Ju, M. G., Lane, S. D., Zeng, X. C. & Zhao, H. Highly efficient and anomalous charge transfer in van der Waals trilayer semiconductors. Nano Lett. 17, 1623–1628 (2017).
Leisgang, N. et al. Giant Stark splitting of an exciton in bilayer MoS2. Nat. Nanotechnol. 15, 901–907 (2020).
Sun, D. et al. Observation of rapid exciton–exciton annihilation in monolayer molybdenum disulfide. Nano Lett. 14, 5625–5629 (2014).
Choi, J. et al. Moiré potential impedes interlayer exciton diffusion in van der Waals heterostructures. Sci. Adv. 6, eaba8866 (2020).
Zhang, L. et al. Highly valley-polarized singlet and triplet interlayer excitons in van der Waals heterostructure. Phys. Rev. B 100, 041402 (2019).
Wang, T. et al. Giant valley-Zeeman splitting from spin-singlet and spin-triplet interlayer excitons in WSe2/MoSe2 heterostructure. Nano Lett. 20, 694–700 (2020).
Yu, J. et al. Observation of double indirect interlayer exciton in WSe2/WS2 heterostructure. Opt. Express 28, 13260 (2020).
Laikhtman, B. & Rapaport, R. Exciton correlations in coupled quantum wells and their luminescence blue shift. Phys. Rev. B 80, 195313 (2009).
McGilly, L. J. et al. Visualization of moiré superlattices. Nat. Nanotechnol. 15, 580–584 (2020).
Li, X., Wu, F. & Macdonald, A. H. Electronic structure of single-twist trilayer graphene. Preprint at http://arxiv.org/abs/1907.12338 (2019).
Zhang, Y. H., Sheng, D. N. & Vishwanath, A. SU(4) chiral spin liquid, exciton supersolid, and electric detection in moiré bilayers. Phys. Rev. Lett. 127, 247701 (2021).
Miao, S. et al. Strong interaction between interlayer excitons and correlated electrons in WSe2/WS2 moiré superlattice. Nat. Commun. 12, 8–13 (2021).
Bai, Y. et al. Evidence for exciton crystals in a 2D semiconductor heterotrilayer. Preprint at http://arxiv.org/abs/2207.09601 (2022).
Li, W. et al. Quadrupolar–dipolar excitonic transition in a tunnel-coupled van der Waals heterotrilayer. Nat. Mater. https://doi.org/10.1038/s41563-023-01667-1 (2023).
Wang, L. et al. One-dimensional electrical contact to a two-dimensional material. Science 342, 614–617 (2013).
Jain, A. et al. One-dimensional edge contacts to a monolayer semiconductor. Nano Lett. 19, 6914–6923 (2019).
Li, H. et al. Imaging moiré flat bands in three-dimensional reconstructed WSe2/WS2 superlattices. Nat. Mater. 20, 945–950 (2021).
Acknowledgements
This work was supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division under award number DE-SC0020115 and, for sample preparation, under SLAC FWP 100459. Additional support was provided for sample preparation and analysis by the Betty and Gordon Moore Foundation EPiQS Initiative through Grant No. GBMF9462 and for a graduate fellowship for J.H. by NTT Research. Sample fabrication and the PFM characterization were performed at the Stanford Nano Shared Facilities, supported by the National Science Foundation under award ECCS-2026822. K.W. and T.T. acknowledge support from the Japan Society for the Promotion of Science (KAKENHI Grant Numbers 21H05233 and 23H02052) and the World Premier International Research Center Initiative, Ministry of Education, Culture, Sports, Science and Technology, Japan.
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L.Y. conceived the project. K.P. and L.Y. fabricated the samples. L.Y. and K.P. performed the optical measurements. K.P. and J.H. performed the PFM measurements. T.T. and K.W. synthesized the h-BN crystals. T.F.H. supervised the project. L.Y., T.F.H. and K.P. wrote the paper with input from all authors.
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Yu, L., Pistunova, K., Hu, J. et al. Observation of quadrupolar and dipolar excitons in a semiconductor heterotrilayer. Nat. Mater. 22, 1485–1491 (2023). https://doi.org/10.1038/s41563-023-01678-y
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DOI: https://doi.org/10.1038/s41563-023-01678-y
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