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Broken mirror symmetry in excitonic response of reconstructed domains in twisted MoSe₂/MoSe₂ bilayers

Sung, Jiho and Zhou, You and Scuri, Giovanni and Zólyomi, Viktor and Andersen, Trond I. and Yoo, Hyobin and Wild, Dominik S. and Joe, Andrew Y. and Gelly, Ryan J. and Heo, Hoseok and Magorrian, Samuel J. and Bérubé, Damien and Valdivia, Andrés M. Mier and Taniguchi, Takashi and Watanabe, Kenji and Lukin, Mikhail D. and Kim, Philip and Fal’ko, Vladimir I. and Park, Hongkun (2020) Broken mirror symmetry in excitonic response of reconstructed domains in twisted MoSe₂/MoSe₂ bilayers. Nature Nanotechnology, 15 (9). pp. 750-754. ISSN 1748-3387.

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Van der Waals heterostructures obtained via stacking and twisting have been used to create moiré superlattices, enabling new optical and electronic properties in solid-state systems. Moiré lattices in twisted bilayers of transition metal dichalcogenides (TMDs) result in exciton trapping, host Mott insulating and superconducting states6 and act as unique Hubbard systems whose correlated electronic states can be detected and manipulated optically. Structurally, these twisted heterostructures feature atomic reconstruction and domain formation. However, due to the nanoscale size of moiré domains, the effects of atomic reconstruction on the electronic and excitonic properties have not been systematically investigated. Here we use near-0°-twist-angle MoSe₂/MoSe₂ bilayers with large rhombohedral AB/BA domains to directly probe the excitonic properties of individual domains with far-field optics. We show that this system features broken mirror/inversion symmetry, with the AB and BA domains supporting interlayer excitons with out-of-plane electric dipole moments in opposite directions. The dipole orientation of ground-state Γ–K interlayer excitons can be flipped with electric fields, while higher-energy K–K interlayer excitons undergo field-asymmetric hybridization with intralayer K–K excitons. Our study reveals the impact of crystal symmetry on TMD excitons and points to new avenues for realizing topologically non-trivial systems, exotic metasurfaces, collective excitonic phases and quantum emitter arrays via domain-pattern engineering.

Item Type:Article
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URLURL TypeDescription ReadCube access Paper
Zhou, You0000-0002-9854-545X
Scuri, Giovanni0000-0003-1050-3114
Wild, Dominik S.0000-0001-7994-7077
Magorrian, Samuel J.0000-0002-5727-9722
Watanabe, Kenji0000-0003-3701-8119
Lukin, Mikhail D.0000-0002-8658-1007
Kim, Philip0000-0002-8255-0086
Fal’ko, Vladimir I.0000-0003-0828-0310
Park, Hongkun0000-0001-9576-8829
Additional Information:© 2020 Nature Publishing Group. Received 03 December 2019; Accepted 03 June 2020; Published 13 July 2020. We thank B. Urbaszek for helpful discussions. We acknowledge support from the DoD Vannevar Bush Faculty Fellowship (N00014-16-1-2825 for H.P., N00014-18-1-2877 for P.K.), NSF (PHY-1506284 for H.P. and M.D.L.), NSF CUA (PHY-1125846 for H.P. and M.D.L.), AFOSR MURI (FA9550-17-1-0002), ARL (W911NF1520067 for H.P. and M.D.L.), the Gordon and Betty Moore Foundation (GBMF4543 for P.K.), ONR MURI (N00014-15-1-2761 for P.K.), and Samsung Electronics (for P.K. and H.P.). V.I.F. acknowledges EPSRC grants no. EP/S019367/1, EP/S030719/1, EP/N010345/1, ERC Synergy Grant Hetero2D, Lloyd’s Register Foundation Nanotechnology Grant, European Graphene Flagship Project and European Quantum Technologies Project 2D-SIPC. The device fabrication was carried out at the Harvard Center for Nanoscale Systems. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan and the CREST (JPMJCR15F3), JST. D.B. acknowledges support from the Summer Undergraduate Research Fellowship at Caltech. Data availability: The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request. Author Contributions: H.P., P.K., J.S., Y.Z., G.S., H.Y. and D.S.W. conceived the study, and J.S., Y.Z., G.S., T.I.A, A.Y.J., R.J.G., D.B. and A.M.M.V. fabricated the devices and performed the optical spectroscopy. H.P. V.I.F. J.S., Y.Z., G.S., V.Z., T.I.A. and D.S.W. analysed the data. V.I.F., V.Z. and S.J.M. performed the DFT calculations. H.Y. performed electron microscopy measurements. H.H. performed MoSe₂ crystal growth. T.T. and K.W. performed h-BN crystal growth. J.S., Y.Z., G.S., T.I.A, M.D.L., P.K., V.I.F. and H.P. wrote the manuscript with extensive input from all authors. H.P., V.I.F., P.K. and M.D.L. supervised the project. The authors declare no competing interests.
Funding AgencyGrant Number
Vannever Bush Faculty FellowshipUNSPECIFIED
Office of Naval Research (ONR)N00014-16-1-2825
Office of Naval Research (ONR)N00014-18-1-2877
Air Force Office of Scientific Research (AFOSR)FA9550-17-1-0002
Army Research LaboratoryW911NF1520067
Gordon and Betty Moore FoundationGBMF4543
Office of Naval Research (ONR)N00014-15-1-2761
Samsung ElectronicsUNSPECIFIED
Engineering and Physical Sciences Research Council (EPSRC)EP/S019367/1
Engineering and Physical Sciences Research Council (EPSRC)EP/S030719/1
Engineering and Physical Sciences Research Council (EPSRC)EP/N010345/1
European Research Council (ERC)UNSPECIFIED
Lloyd’s Register FoundationUNSPECIFIED
Ministry of Education, Culture, Sports, Science and Technology (MEXT)UNSPECIFIED
Japan Science and Technology AgencyJPMJCR15F3
Caltech Summer Undergraduate Research Fellowship (SURF)UNSPECIFIED
Subject Keywords:Electronic properties and materials; Photonic devices; Two-dimensional materials
Issue or Number:9
Record Number:CaltechAUTHORS:20200720-103927415
Persistent URL:
Official Citation:Sung, J., Zhou, Y., Scuri, G. et al. Broken mirror symmetry in excitonic response of reconstructed domains in twisted MoSe2/MoSe2 bilayers. Nat. Nanotechnol. 15, 750–754 (2020).
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104446
Deposited By: Tony Diaz
Deposited On:20 Jul 2020 17:58
Last Modified:17 Sep 2020 17:32

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