Two-dimensional (2D) materials1,2,3,4,5 offer a unique platform from which to explore the physics of topology and many-body phenomena. New properties can be generated by filling the van der Waals gap of 2D materials with intercalants6,7; however, post-growth intercalation has usually been limited to alkali metals8,9,10. Here we show that the self-intercalation of native atoms11,12 into bilayer transition metal dichalcogenides during growth generates a class of ultrathin, covalently bonded materials, which we name ic-2D. The stoichiometry of these materials is defined by periodic occupancy patterns of the octahedral vacancy sites in the van der Waals gap, and their properties can be tuned by varying the coverage and the spatial arrangement of the filled sites7,13. By performing growth under high metal chemical potential14,15 we can access a range of tantalum-intercalated TaS(Se)y, including 25% Ta-intercalated Ta9S16, 33.3% Ta-intercalated Ta7S12, 50% Ta-intercalated Ta10S16, 66.7% Ta-intercalated Ta8Se12 (which forms a Kagome lattice) and 100% Ta-intercalated Ta9Se12. Ferromagnetic order was detected in some of these intercalated phases. We also demonstrate that self-intercalated V11S16, In11Se16 and FexTey can be grown under metal-rich conditions. Our work establishes self-intercalation as an approach through which to grow a new class of 2D materials with stoichiometry- or composition-dependent properties.
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The main data supporting the findings of this study are available within the paper and its Supplementary Information. Additional data are available from the corresponding authors upon reasonable request.
The Python code is available in the Supplementary Information.
Chhowalla, M. et al. The chemistry of two-dimensional layered transition metal dichalcogenide nanosheets. Nat. Chem. 5, 263–275 (2013).
Zhou, J. et al. A library of atomically thin metal chalcogenides. Nature 556, 355–359 (2018).
Jin, C. et al. Ultrafast dynamics in van der Waals heterostructures. Nat. Nanotechnol. 13, 994–1003 (2018).
Wang, C. et al. Monolayer atomic crystal molecular superlattices. Nature 555, 231–236 (2018).
Novoselov, K. S. et al. Two-dimensional atomic crystals. Proc. Natl Acad. Sci. USA 102, 10451–10453 (2005).
Wan, J. et al. Tuning two-dimensional nanomaterials by intercalation: materials, properties and applications. Chem. Soc. Rev. 45, 6742–6765 (2016).
Friend, R. H. & Yoffe, A. D. Electronic properties of intercalation complexes of the transition metal dichalcogenides. Adv. Phys. 36, 1–94 (1987).
Wang, X., Shen, X., Wang, Z., Yu, R. & Chen, L. Atomic-scale clarification of structural transition of MoS2 upon sodium intercalation. ACS Nano 8, 11394–11400 (2014).
Tan, S. J. R. et al. Chemical stabilization of 1T′ phase transition metal dichalcogenides with giant optical Kerr nonlinearity. J. Am. Chem. Soc. 139, 2504–2511 (2017).
Kanetani, K. et al. Ca intercalated bilayer graphene as a thinnest limit of superconducting C6Ca. Proc. Natl Acad. Sci. USA 109, 19610–19613 (2012).
Yang, J. et al. Ultrahigh-current-density niobium disulfide catalysts for hydrogen evolution. Nat. Mater. 18, 1309–1314 (2019).
Cui, F. et al. Controlled growth and thickness-dependent conduction-type transition of 2D ferrimagnetic Cr2S3 semiconductors. Adv. Mater. 32, 1905896 (2020).
Mortazavi, M., Wang, C., Deng, J., Shenoy, V. B. & Medhekar, N. V. Ab initio characterization of layered MoS2 as anode for sodium-ion batteries. J. Power Sources 268, 279–286 (2014).
Fu, D. et al. Molecular beam epitaxy of highly crystalline monolayer molybdenum disulfide on hexagonal boron nitride. J. Am. Chem. Soc. 139, 9392–9400 (2017).
Chen, J. et al. Homoepitaxial growth of large-scale highly organized transition metal dichalcogenide patterns. Adv. Mater. 30, 1704674 (2018).
Liao, M. et al. Twist angle-dependent conductivities across MoS2/graphene heterojunctions. Nat. Commun. 9, 4068 (2018).
Koski, K. J. et al. Chemical intercalation of zerovalent metals into 2D layered Bi2Se3 nanoribbons. J. Am. Chem. Soc. 134, 13773–13779 (2012).
Guilmeau, E., Barbier, T., Maignan, A. & Chateigner, D. Thermoelectric anisotropy and texture of intercalated TiS2. Appl. Phys. Lett. 111, 133903 (2017).
Wang, M. et al. Chemical intercalation of heavy metal, semimetal, and semiconductor atoms into 2D layered chalcogenides. 2D Mater. 5, 045005 (2018).
Dungey, K. E., Curtis, M. D. & Penner-Hahn, J. E. Structural characterization and thermal stability of MoS2 intercalation compounds. Chem. Mater. 10, 2152–2161 (1998).
Gong, Y. et al. Spatially controlled doping of two-dimensional SnS2 through intercalation for electronics. Nat. Nanotechnol. 13, 294–299 (2018).
Chen, Z. et al. Interface confined hydrogen evolution reaction in zero valent metal nanoparticles-intercalated molybdenum disulfide. Nat. Commun. 8, 14548 (2017).
Liu, C. et al. Dynamic Ag+-intercalation with AgSnSe2 nano-precipitates in Cl-doped polycrystalline SnSe2 toward ultra-high thermoelectric performance. J. Mater. Chem. A 7, 9761–9772 (2019).
Bouwmeester, H. J. M., van der Lee, A., van Smaalen, S. & Wiegers, G. A. Order–disorder transition in silver-intercalated niobium disulfide compounds. II. Magnetic and electrical properties. Phys. Rev. B 43, 9431–9435 (1991).
Wan, C. et al. Flexible n-type thermoelectric materials by organic intercalation of layered transition metal dichalcogenide TiS2. Nat. Mater. 14, 622–627 (2015).
Jeong, S. et al. Tandem intercalation strategy for single-layer nanosheets as an effective alternative to conventional exfoliation processes. Nat. Commun. 6, 5763 (2015).
O’Brien, E. S. et al. Single-crystal-to-single-crystal intercalation of a low-bandgap superatomic crystal. Nat. Chem. 9, 1170–1174 (2017).
Kumar, P., Skomski, R. & Pushpa, R. Magnetically ordered transition-metal-intercalated WSe2. ACS Omega 2, 7985–7990 (2017).
Kim, S. et al. Interstitial Mo-assisted photovoltaic effect in multilayer MoSe2 phototransistors. Adv. Mater. 30, 1705542 (2018).
Zhang, M. et al. Electron density optimization and the anisotropic thermoelectric properties of Ti self-intercalated Ti1+xS2 compounds. ACS Appl. Mater. Interfaces 10, 32344–32354 (2018).
Wang, S. et al. Shape evolution of monolayer MoS2 crystals grown by chemical vapor deposition. Chem. Mater. 26, 6371–6379 (2014).
Zhao, X. et al. Mo-terminated edge reconstructions in nanoporous molybdenum disulfide film. Nano Lett. 18, 482–490 (2018).
Mounet, N. et al. Two-dimensional materials from high-throughput computational exfoliation of experimentally known compounds. Nat. Nanotechnol. 13, 246–252 (2018).
Azizi, A. et al. Spontaneous formation of atomically thin stripes in transition metal dichalcogenide monolayers. Nano Lett. 16, 6982–6987 (2016).
Motome, Y., Furukawa, N. & Nagaosa, N. Competing orders and disorder-induced insulator to metal transition in manganites. Phys. Rev. Lett. 91, 167204 (2003).
Parish, M. M. & Littlewood, P. B. Non-saturating magnetoresistance in heavily disordered semiconductors. Nature 426, 162–165 (2003).
Jiang, Z. et al. Structural and proximity-induced ferromagnetic properties of topological insulator-magnetic insulator heterostructures. AIP Adv. 6, 055809 (2016).
Jiang, Z. et al. Independent tuning of electronic properties and induced ferromagnetism in topological insulators with heterostructure approach. Nano Lett. 15, 5835–5840 (2015).
Nagaosa, N., Sinova, J., Onoda, S., MacDonald, A. H. & Ong, N. P. Anomalous Hall effect. Rev. Mod. Phys. 82, 1539–1592 (2010).
Zener, C. Interaction between the d shells in the transition metals. Phys. Rev. 81, 440–444 (1951).
Coelho, P. M. et al. Charge density wave state suppresses ferromagnetic ordering in VSe2 monolayers. J. Phys. Chem. C 123, 14089–14096 (2019).
Haastrup, S. et al. The computational 2D materials database: high-throughput modeling and discovery of atomically thin crystals. 2D Mater. 5, 042002 (2018).
Karthikeyan, J., Komsa, H.-P., Batzill, M. & Krasheninnikov, A. V. Which transition metal atoms can be embedded into two-dimensional molybdenum dichalcogenides and add magnetism? Nano Lett. 19, 4581–4587 (2019).
Wang, H. et al. High-quality monolayer superconductor NbSe2 grown by chemical vapour deposition. Nat. Commun. 8, 394 (2017).
Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab Initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996).
Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).
Monkhorst, H. J. & Pack, J. D. Special points for Brillouin-zone integrations. Phys. Rev. B 13, 5188–5192 (1976).
Dudarev, S. L. Electron-energy-loss spectra and the structural stability of nickel oxide: An LSDA+U study. Phys. Rev. B 57, 1505 (1998).
Enkovaara, J. et al. Electronic structure calculations with GPAW: a real-space implementation of the projector augmented-wave method. J. Phys. Condens. Matter 22, 253202 (2010).
Wellendorff, J. et al. Density functionals for surface science: exchange-correlation model development with Bayesian error estimation. Phys. Rev. B 85, 235149 (2012).
K.P.L. thanks A*STAR Project ‘Scalable Growth of Ultrathin Ferroelectric Materials for Memory Technologies’ (grant number A1983c0035) and support from the Centre for Advanced 2D Materials, National University of Singapore. W.Z. acknowledges support from the National Key R&D Program of China (2018YFA0305800) and the Natural Science Foundation of China (51622211). S.J.P. is grateful to the National University of Singapore for funding and the Ministry of Education (MOE) for a Tier 2 grant ‘Atomic scale understanding and optimization of defects in 2D materials’ (MOE2017-T2-2-139). Z.L. thanks the MOE for a Tier 2 grant (2017-T2-2-136) and a Tier 3 grant (2018-T3-1-002), and the A*STAR QTE programme. X.L. acknowledges support from the National Natural Science Foundation of China (grant number 11804286) and the Fundamental Research Funds for the Central Universities (grant number 19lgpy263). DFT calculations were performed using resources of the National Supercomputer Center in Guangzhou supported by the Special Program for Applied Research on Super Computation of the NSFC Guangdong Joint Fund (second phase). K.S.T. acknowledges funding from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (grant number 773122, LIMA). The Center for Nanostructured Graphene is sponsored by the Danish National Research Foundation, project DNRF103. We thank J. P. Shi, F. F. Cui and Y. F. Zhang for providing high-quality CVD samples.
The authors declare no competing interests.
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This file contains Supplementary Text and Data, including Supplementary Figures 1-41, Supplementary Tables 1-3 and Supplementary References.
This file contains the Phython Code.
The migration paths of intercalated Ta atoms were in situ tracked by sequential STEM imaging under the e-beam irradiation.
The migration paths of intercalated Ta atoms were in situ tracked by sequential STEM imaging under the e-beam irradiation. The mobility of surface Ta atoms are much higher than that of intercalated Ta atoms.
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Zhao, X., Song, P., Wang, C. et al. Engineering covalently bonded 2D layered materials by self-intercalation. Nature 581, 171–177 (2020). https://doi.org/10.1038/s41586-020-2241-9
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