Abstract
In moiré crystals formed by stacking van der Waals materials, surprisingly diverse correlated electronic phases and optical properties can be realized by a subtle change in the twist angle. Here, we discover that phonon spectra are also renormalized in MoS2 twisted bilayers, adding an insight to moiré physics. Over a range of small twist angles, the phonon spectra evolve rapidly owing to ultra-strong coupling between different phonon modes and atomic reconstructions of the moiré pattern. We develop a low-energy continuum model for phonons that overcomes the outstanding challenge of calculating the properties of large moiré supercells and successfully captures the essential experimental observations. Remarkably, simple optical spectroscopy experiments can provide information on strain and lattice distortions in moiré crystals with nanometre-size supercells. The model promotes a comprehensive and unified understanding of the structural, optical and electronic properties of moiré superlattices.
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Data availability
All relevant data are available from the authors upon reasonable request.
Code availability
All relevant codes are available from the authors upon reasonable request.
Change history
06 April 2021
A Correction to this paper has been published: https://doi.org/10.1038/s41563-021-00998-1
References
Zhang, C. et al. Interlayer couplings, moiré patterns, and 2D electronic superlattices in MoS2/WSe2 hetero-bilayers. Sci. Adv. 3, e1601459 (2017).
Tran, K. et al. Evidence for moiré excitons in van der Waals heterostructures. Nature 567, 71–75 (2019).
Kim, K. et al. van der Waals heterostructures with high accuracy rotational alignment. Nano Lett. 16, 1989–1995 (2016).
Cao, Y. et al. Unconventional superconductivity in magic-angle graphene superlattices. Nature 556, 43–50 (2018).
Yankowitz, M. et al. Tuning superconductivity in twisted bilayer graphene. Science 363, 1059–1064 (2019).
Sharpe, A. L. et al. Emergent ferromagnetism near three-quarters filling in twisted bilayer graphene. Science 365, 605–608 (2019).
Serlin, M. et al. Intrinsic quantized anomalous hall effect in a moiré heterostructure. Science 367, 900–903 (2020).
Cao, Y. et al. Correlated insulator behaviour at half-filling in magic-angle graphene superlattices. Nature 556, 80–84 (2018).
Regan, E. C. et al. Mott and generalized Wigner crystal states in WSe2/WS2 moiré superlattices. Nature 579, 359–363 (2020).
Tang, Y. et al. Simulation of Hubbard model physics in WSe2/WS2 moiré superlattices. Nature 579, 353–358 (2020).
Shimazaki, Y. et al. Strongly correlated electrons and hybrid excitons in a moiré heterostructure. Nature 580, 472–477 (2020).
Naik, M. H. & Jain, M. Ultraflatbands and shear solitons in moiré patterns of twisted bilayer transition metal dichalcogenides. Phys. Rev. Lett. 121, 266401 (2018).
Wang, L. et al. Correlated electronic phases in twisted bilayer transition metal dichalcogenides. Nat. Mater. 19, 861–866 (2020).
Gadelha, A. C. et al. Localization of lattice dynamics in low-angle twisted bilayer graphene. Nature 590, 405–409 (2021).
Carr, S. et al. Relaxation and domain formation in incommensurate two-dimensional heterostructures. Phys. Rev. B 98, 224102 (2018).
Sushko, A. et al. High resolution imaging of reconstructed domains and moiré patterns in functional van der Waals heterostructure devices. Preprint at https://arXiv.org/abs/1912.07446 (2019).
Weston, A. et al. Atomic reconstruction in twisted bilayers of transition metal dichalcogenides. Nat. Nanotechnol. 15, 592–597 (2020).
McGilly, L. J. et al. Visualization of moiré superlattices. Nat. Nanotechnol. 15, 580–584 (2020).
Jung, J., DaSilva, A. M., MacDonald, A. H. & Adam, S. Origin of band gaps in graphene on hexagonal boron nitride. Nat. Commun. 6, 6308 (2015).
Rosenberger, M. R. et al. Twist angle-dependent atomic reconstruction and moiré patterns in transition metal dichalcogenide heterostructures. ACS Nano 14, 4550–4558 (2020).
Yoo, H. et al. Atomic and electronic reconstruction at the van der Waals interface in twisted bilayer graphene. Nat. Mater. 18, 448–453 (2019).
Zhang, K. & Tadmor, E. B. Structural and electron diffraction scaling of twisted graphene bilayers. J. Mech. Phys. Solids 112, 225–238 (2018).
Alden, J. S. et al. Strain solitons and topological defects in bilayer graphene. Proc. Natl Acad. Sci. USA 110, 11256–11260 (2013).
Huang, S. et al. Low-frequency interlayer Raman modes to probe interface of twisted bilayer MoS2. Nano Lett. 16, 1435–1444 (2016).
Nam, N. N. & Koshino, M. Lattice relaxation and energy band modulation in twisted bilayer graphene. Phys. Rev. B 96, 075311 (2017).
Molina-Sánchez, A. & Wirtz, L. Phonons in single-layer and few-layer MoS2 and WS2. Phys. Rev. B 84, 155413 (2011).
Tan, P. et al. The shear mode of multilayer graphene. Nat. Mater. 11, 294–300 (2012).
Zhang, X. et al. Raman spectroscopy of shear and layer breathing modes in multilayer MoS2. Phys. Rev. B 87, 115413 (2013).
Zhao, Y. et al. Interlayer breathing and shear modes in few-trilayer MoS2 and WSe2. Nano Lett. 13, 1007–1015 (2013).
Lin, M.-L. et al. Cross-dimensional electron-phonon coupling in van der Waals heterostructures. Nat. Commun. 10, 2419 (2019).
Lee, C. et al. Anomalous lattice vibrations of single- and few-layer MoS2. ACS Nano 4, 2695–2700 (2010).
Verble, J. L. & Wieting, T. J. Lattice mode degeneracy in MoS2 and other layer compounds. Phys. Rev. Lett. 25, 362–364 (1970).
Li, H. et al. From bulk to monolayer MoS2: evolution of Raman scattering. Adv. Funct. Mater. 22, 1385–1390 (2012).
Puretzky, A. A. et al. Twisted MoSe2 bilayers with variable local stacking and interlayer coupling revealed by low-frequency Raman spectroscopy. ACS Nano 10, 2736–2744 (2016).
Holler, J. et al. Low-frequency Raman scattering in WSe2–MoSe2 heterobilayers: evidence for atomic reconstruction. Appl. Phys. Lett. 117, 013104 (2020).
Liao, M. et al. Precise control of the interlayer twist angle in large scale MoS2 homostructures. Nat. Commun. 11, 2153 (2020).
Debnath, R. et al. Evolution of high-frequency Raman modes and their doping dependence in twisted bilayer MoS2. Nanoscale 12, 17272–17280 (2020).
Cuscó, R., Gil, B., Cassabois, G. & Artús, L. Temperature dependence of Raman-active phonons and anharmonic interactions in layered hexagonal BN. Phys. Rev. B 94, 155435 (2016).
Lee, J.-U. et al. Strain-shear coupling in bilayer MoS2. Nat. Commun. 8, 1370 (2017).
Wang, Y., Cong, C., Qiu, C. & Yu, T. Raman spectroscopy study of lattice vibration and crystallographic orientation of monolayer MoS2 under uniaxial strain. Small 9, 2857–2861 (2013).
Lin, M.-L. et al. Moiré phonons in twisted bilayer MoS2. ACS Nano 12, 8770–8780 (2018).
Koshino, M. & Son, Y.-W. Moiré phonons in twisted bilayer graphene. Phys. Rev. B 100, 075416 (2019).
Campos-Delgado, J., Cançado, L. G., Achete, C. A., Jorio, A. & Raskin, J.-P. Raman scattering study of the phonon dispersion in twisted bilayer graphene. Nano Res. 6, 269–274 (2013).
He, R. et al. Observation of low energy Raman modes in twisted bilayer graphene. Nano Lett. 13, 3594–3601 (2013).
Cocemasov, A. I., Nika, D. L. & Balandin, A. A. Phonons in twisted bilayer graphene. Phys. Rev. B 88, 035428 (2013).
Jorio, A. & Cançado, L. G. Raman spectroscopy of twisted bilayer graphene. Solid State Commun. 175, 3–12 (2013).
Maity, I., Naik, M. H., Maiti, P. K., Krishnamurthy, H. & Jain, M. Phonons in twisted transition-metal dichalcogenide bilayers: ultrasoft phasons and a transition from a superlubric to a pinned phase. Phys. Rev. Res. 2, 013335 (2020).
Cocemasov, A. I., Nika, D. L. & Balandin, A. A. Phonons in twisted bilayer graphene. Phys. Rev. B 88, 035428 (2013).
Jung, J., Raoux, A., Qiao, Z. & MacDonald, A. H. Ab initio theory of moiré superlattice bands in layered two-dimensional materials. Phys. Rev. B 89, 205414 (2014).
Bistritzer, R. & MacDonald, A. H. Moiré bands in twisted double-layer graphene. Proc. Natl Acad. Sci. USA 108, 12233–12237 (2011).
Kresse, G. & Hafner, J. Ab initio molecular dynamics for liquid metals. Phys. Rev. B 47, 558–561 (1993).
Kresse, G. & Hafner, J. Ab initio molecular-dynamics simulation of the liquid-metal–amorphous-semiconductor transition in germanium. Phys. Rev. B 49, 251–271 (1994).
Acknowledgements
The spectroscopy experiments at the University of Texas at Austin (J.Q.) were primarily funded by the US Department of Energy, Office of Basic Energy Sciences under grant DE-SC0019398 and a grant from the University of Texas. Material preparation was funded by the Welch Foundation via grant F-1662. The collaboration between the X.L., C.-K.S., K.L. and A.H.M. groups is facilitated by the National Science Foundation Materials Research Science and Engineering Centers (MRSEC) under DMR-1720595, which funded J.C. and J.E. partially. L.L. and F.L. acknowledge support by the TU-D doctoral programme of TU Wien, as well as from the Austrian Science Fund (FWF), project I-3827, and L.L. acknowledges additional support from the Austrian Marshall Plan Foundation. We acknowledge discussions with S. Reichardt and the use of facilities and instrumentation supported by the National Science Foundation through the Center for Dynamics and Control of Materials and National Science Foundation MRSEC under cooperative agreement no. DMR-1720595. P.-H.T. and M.-L.L. acknowledge support from the National Natural Science Foundation of China (grant nos 12004377 and 11874350), CAS Key Research Program of Frontier Sciences (grant no. ZDBS-LY-SLH004) and China Postdoctoral Science Foundation (grant no. 2019TQ0317). The PFM work (D.L. and K.L.) was supported by National Science Foundation DMR-2004536 and Welch Foundation grant F-1814. X.L. gratefully acknowledges the support of sample preparations from the Welch Foundation via grant F-1662. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan, grant no. JPMXP0112101001; JSPS KAKENHI, grant no. JP20H00354; and the CREST(JPMJCR15F3), JST.
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J.Q. led the optical experiments, and M.-L.L., C.-Y.W., W.-T.H., J.E. and J.C. assisted with the experiment. L.L. led the theoretical calculations, and J.Z. contributed to the theoretical discussions. D.L. performed the PFM measurements. J.Q. and C.Y. prepared the TBL samples. T.T. and K.W. provided the hBN sample. J.Q., L.L., F.L. and X.L. wrote the manuscript. X.L., F.L., A.H.M., P.-H.T., K.L. and C.-K.S. supervised the project. All authors discussed the results.
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Quan, J., Linhart, L., Lin, ML. et al. Phonon renormalization in reconstructed MoS2 moiré superlattices. Nat. Mater. 20, 1100–1105 (2021). https://doi.org/10.1038/s41563-021-00960-1
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DOI: https://doi.org/10.1038/s41563-021-00960-1