Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Giant spin Hall effect in AB-stacked MoTe2/WSe2 bilayers

Nature Nanotechnology volume 19, pages 28–33 (2024)Cite this article

Subjects

Abstract

The spin Hall effect (SHE), in which an electrical current generates a transverse spin current, plays an important role in spintronics for the generation and manipulation of spin-polarized electrons. The phenomenon originates from spin–orbit coupling. In general, stronger spin–orbit coupling favours larger SHEs but shorter spin relaxation times and diffusion lengths. However, correlated magnetic materials often do not support large SHEs. Achieving large SHEs, long-range spin transport and magnetism simultaneously in a single material is attractive for spintronics applications but has remained a challenge. Here we demonstrate a giant intrinsic SHE coexisting with ferromagnetism in AB-stacked MoTe2/WSe2 moiré bilayers by direct magneto-optical imaging. Under moderate electrical currents with density <1 A m−1, we observe spin accumulation on transverse sample edges that nearly saturates the spin density. We also demonstrate long-range spin Hall transport and efficient non-local spin accumulation that is limited only by the device size (about 10 µm). The gate dependence shows that the giant SHE occurs only near the interaction-driven Chern insulating state. At low temperatures, it emerges after the quantum anomalous Hall breakdown. Our results demonstrate moiré engineering of Berry curvature and electronic correlation for potential spintronics applications.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Direct observation of the SHE.
Fig. 2: Giant spin accumulation and QAH breakdown.
Fig. 3: Doping-dependent non-local spin Hall transport.

Similar content being viewed by others

Data availability

Source data are provided with this paper. All other data are available from the corresponding authors upon reasonable request.

References

  1. Sinova, J., Valenzuela, S. O., Wunderlich, J., Back, C. H. & Jungwirth, T. Spin Hall effects. Rev. Mod. Phys. 87, 1213–1260 (2015).

    Article  Google Scholar 

  2. Rojas-Sánchez, J.-C. et al. Spin to charge conversion at room temperature by spin pumping into a new type of topological insulator: α-Sn films. Phys. Rev. Lett. 116, 096602 (2016).

    Article  Google Scholar 

  3. Li, C. H. et al. Electrical detection of charge-current-induced spin polarization due to spin-momentum locking in Bi2Se3. Nat. Nanotechnol. 9, 218–224 (2014).

    Article  CAS  Google Scholar 

  4. Jungwirth, T., Wunderlich, J. & Olejník, K. Spin Hall effect devices. Nat. Mater. 11, 382–390 (2012).

    Article  CAS  Google Scholar 

  5. Kato, Y. K., Myers, R. C., Gossard, A. C. & Awschalom, D. D. Observation of the spin Hall effect in semiconductors. Science 306, 1910–1913 (2004).

    Article  CAS  Google Scholar 

  6. Wunderlich, J., Kaestner, B., Sinova, J. & Jungwirth, T. Experimental observation of the spin-Hall effect in a two-dimensional spin-orbit coupled semiconductor system. Phys. Rev. Lett. 94, 047204 (2005).

    Article  CAS  Google Scholar 

  7. Liu, L. et al. Spin-torque switching with the giant spin Hall effect of tantalum. Science 336, 555–558 (2012).

    Article  CAS  Google Scholar 

  8. Liu, L., Lee, O. J., Gudmundsen, T. J., Ralph, D. C. & Buhrman, R. A. Current-induced switching of perpendicularly magnetized magnetic layers using spin torque from the spin Hall effect. Phys. Rev. Lett. 109, 096602 (2012).

    Article  Google Scholar 

  9. Žutić, I., Fabian, J. & Das Sarma, S. Spintronics: fundamentals and applications. Rev. Mod. Phys. 76, 323–410 (2004).

    Article  Google Scholar 

  10. Gibbons, J. D., MacNeill, D., Buhrman, R. A. & Ralph, D. C. Reorientable spin direction for spin current produced by the anomalous Hall effect. Phys. Rev. Appl. 9, 064033 (2018).

    Article  CAS  Google Scholar 

  11. Iihama, S. et al. Spin-transfer torque induced by the spin anomalous Hall effect. Nat. Electron. 1, 120–123 (2018).

    Article  Google Scholar 

  12. Xu, X., Yao, W., Xiao, D. & Heinz, T. F. Spin and pseudospins in layered transition metal dichalcogenides. Nat. Phys. 10, 343–350 (2014).

    Article  CAS  Google Scholar 

  13. Xiao, D., Yao, W. & Niu, Q. Valley-contrasting physics in graphene: magnetic moment and topological transport. Phys. Rev. Lett. 99, 236809 (2007).

    Article  Google Scholar 

  14. Yao, W., Xiao, D. & Niu, Q. Valley-dependent optoelectronics from inversion symmetry breaking. Phys. Rev. B 77, 235406 (2008).

    Article  Google Scholar 

  15. Xiao, D., Liu, G.-B., Feng, W., Xu, X. & Yao, W. Coupled spin and valley physics in monolayers of MoS2 and other Group-VI dichalcogenides. Phys. Rev. Lett. 108, 196802 (2012).

    Article  Google Scholar 

  16. Mak, K. F., Xiao, D. & Shan, J. Light–valley interactions in 2D semiconductors. Nat. Photonics 12, 451–460 (2018).

    Article  CAS  Google Scholar 

  17. Lee, J., Wang, Z., Xie, H., Mak, K. F. & Shan, J. Valley magnetoelectricity in single-layer MoS2. Nat. Mater. 16, 887–891 (2017).

    Article  CAS  Google Scholar 

  18. Mak, K. F., McGill, K. L., Park, J. & McEuen, P. L. The valley Hall effect in MoS2 transistors. Science 344, 1489–1492 (2014).

    Article  CAS  Google Scholar 

  19. Tschirhart, C. L. et al. Intrinsic spin Hall torque in a moiré Chern magnet. Nat. Phys. 19, 807–813 (2023).

    Article  CAS  Google Scholar 

  20. Andrei, E. Y. et al. The marvels of moiré materials. Nat. Rev. Mater. 6, 201–206 (2021).

    Article  CAS  Google Scholar 

  21. Andrei, E. Y. & MacDonald, A. H. Graphene bilayers with a twist. Nat. Mater. 19, 1265–1275 (2020).

    Article  CAS  Google Scholar 

  22. Liu, J. & Dai, X. Orbital magnetic states in moiré graphene systems. Nat. Rev. Phys. 3, 367–382 (2021).

    Article  CAS  Google Scholar 

  23. Mak, K. F. & Shan, J. Semiconductor moiré materials. Nat. Nanotechnol. 17, 686–695 (2022).

    Article  CAS  Google Scholar 

  24. Kennes, D. M. et al. Moiré heterostructures as a condensed-matter quantum simulator. Nat. Phys. 17, 155–163 (2021).

    Article  CAS  Google Scholar 

  25. Devakul, T. & Fu, L. Quantum anomalous Hall effect from inverted charge transfer gap. Phys. Rev. X 12, 021031 (2022).

    CAS  Google Scholar 

  26. Zhang, Y., Devakul, T. & Fu, L. Spin-textured Chern bands in AB-stacked transition metal dichalcogenide bilayers. Proc. Natl Acad. Sci. USA 118, e2112673118 (2021).

    Article  CAS  Google Scholar 

  27. Rademaker, L. Spin-orbit coupling in transition metal dichalcogenide heterobilayer flat bands. Phys. Rev. B 105, 195428 (2022).

    Article  CAS  Google Scholar 

  28. Pan, H., Xie, M., Wu, F. & Das Sarma, S. Topological phases in AB-stacked MoTe2/WSe2: Z2 topological insulators, Chern insulators, and topological charge density waves. Phys. Rev. Lett. 129, 056804 (2022).

    Article  CAS  Google Scholar 

  29. Kane, C. L. & Mele, E. J. Z2 topological order and the quantum spin Hall effect. Phys. Rev. Lett. 95, 146802 (2005).

    Article  CAS  Google Scholar 

  30. Kane, C. L. & Mele, E. J. Quantum spin Hall effect in graphene. Phys. Rev. Lett. 95, 226801 (2005).

    Article  CAS  Google Scholar 

  31. Fengcheng, W., Lovorn, T., Tutuc, E., Martin, I. & MacDonald, A. H. Topological insulators in twisted transition metal dichalcogenide homobilayers. Phys. Rev. Lett. 122, 086402 (2019).

    Article  Google Scholar 

  32. Xie, Y.-M., Zhang, C.-P., Hu, J.-X., Mak, K. F. & Law, K. T. Valley-polarized quantum anomalous Hall state in moiré MoTe2/WSe2 heterobilayers. Phys. Rev. Lett. 128, 026402 (2022).

    Article  CAS  Google Scholar 

  33. Mai, P., Zhao, J., Feldman, B. E. & Phillips, P. W. 1/4 is the new 1/2: Interaction-induced unification of quantum anomalous and spin Hall effects. Preprint at https://doi.org/10.48550/arXiv.2210.11486 (2022).

  34. Zhao, W. et al. Realization of the Haldane Chern insulator in a moiré lattice. Preprint at http://arxiv.org/sabs/2207.02312 (2022).

  35. Li, T. et al. Quantum anomalous Hall effect from intertwined moiré bands. Nature 600, 641–646 (2021).

    Article  CAS  Google Scholar 

  36. Tao, Z. et al. Valley-coherent quantum anomalous Hall state in AB-stacked MoTe2/WSe2 bilayers. Preprint at https://doi.org/10.48550/arXiv.2208.07452 (2022).

  37. Regan, E. C. et al. Mott and generalized Wigner crystal states in WSe2/WS2 moiré superlattices. Nature 579, 359–363 (2020).

    Article  CAS  Google Scholar 

  38. Wang, X. et al. Light-induced ferromagnetism in moiré superlattices. Nature 604, 468–473 (2022).

    Article  CAS  Google Scholar 

  39. Tang, Y. et al. Simulation of Hubbard model physics in WSe2/WS2 moiré superlattices. Nature 579, 353–358 (2020).

    Article  CAS  Google Scholar 

  40. Li, T. et al. Continuous Mott transition in semiconductor moiré superlattices. Nature 597, 350–354 (2021).

    Article  CAS  Google Scholar 

  41. Lau, C. N., Bockrath, M. W., Mak, K. F. & Zhang, F. Reproducibility in the fabrication and physics of moiré materials. Nature 602, 41–50 (2022).

    Article  CAS  Google Scholar 

  42. Yu, S.-B., Sun, S.-H., Zhou, M., Zhang, D. & Chang, K. Current-induced spin polarization in Janus WSSe monolayer. Phys. Rev. B 107, 125426 (2023).

    Article  CAS  Google Scholar 

  43. Yu, S.-B., Zhou, M., Zhang, D. & Chang, K. Spin Hall effect in the monolayer Janus compound MoSSe enhanced by Rashba spin-orbit coupling. Phys. Rev. B 104, 075435 (2021).

    Article  CAS  Google Scholar 

  44. Lee, J., Mak, K. F. & Shan, J. Electrical control of the valley Hall effect in bilayer MoS2 transistors. Nat. Nanotechnol. 11, 421–425 (2016).

    Article  CAS  Google Scholar 

  45. Vila, M. et al. Low-symmetry topological materials for large charge-to-spin interconversion: the case of transition metal dichalcogenide monolayers. Phys. Rev. Res. 3, 043230 (2021).

    Article  CAS  Google Scholar 

  46. Song, P. et al. Coexistence of large conventional and planar spin Hall effect with long spin diffusion length in a low-symmetry semimetal at room temperature. Nat. Mater. 19, 292–298 (2020).

    Article  CAS  Google Scholar 

  47. Bi, Z. & Fu, L. Excitonic density wave and spin-valley superfluid in bilayer transition metal dichalcogenide. Nat. Commun. 12, 642 (2021).

    Article  CAS  Google Scholar 

  48. Wang, L. et al. One-dimensional electrical contact to a two-dimensional material. Science 342, 614–617 (2013).

    Article  CAS  Google Scholar 

  49. Beconcini, M., Taddei, F. & Polini, M. Nonlocal topological valley transport at large valley Hall angles. Phys. Rev. B 94, 121408 (2016).

    Article  Google Scholar 

Download references

Acknowledgements

This work was supported by the National Science Foundation (NSF; Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials) under cooperative agreement Nos. DMR-2039380 (sample and device fabrication) and DMR-1807810 (magneto-optical measurements), the Air Force Office of Scientific Research under award number FA9550-19-1-0390 (transport measurements) and the US Department of Energy, Office of Science, Basic Energy Sciences, under award number DE-SC0019481 (modelling). This research was also funded in part through the Cornell University Materials Research Science and Engineering Center (Grant No. DMR-1719875) and by the Gordon and Betty Moore Foundation (Grant DOI: 10.37807/GBMF11563). It was performed in part at the Cornell NanoScale Facility, a member of the National Nanotechnology Coordinated Infrastructure supported by NSF Grant NNCI-2025233. The growth of the hBN crystals was supported by the Elemental Strategy Initiative of the Ministry of Education, Culture, Sports, Science and Technology, Japan, and the Core Research for Evolutional Science and Technology programme of the Japan Science and Technology Agency (Grant No. JPMJCR15F3). We also acknowledge support from the David and Lucille Packard Fellowship (K.F.M.) and the Kavli Postdoctoral Fellowship (W.Z.).

Author information

Author notes

  1. These authors contributed equally: Zui Tao, Bowen Shen, Wenjin Zhao.

Authors and Affiliations

  1. School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA

    Zui Tao, Bowen Shen, Tingxin Li, Shengwei Jiang, Lizhong Li, Jie Shan & Kin Fai Mak

  2. Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA

    Wenjin Zhao, Jie Shan & Kin Fai Mak

  3. Department of Physics, University of Texas at Austin, Austin, TX, USA

    Nai Chao Hu & Allan H. MacDonald

  4. National Institute for Materials Science, Tsukuba, Japan

    Kenji Watanabe & Takashi Taniguchi

  5. Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, NY, USA

    Jie Shan & Kin Fai Mak

Authors
  1. Zui Tao
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Bowen Shen
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Wenjin Zhao
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Nai Chao Hu
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Tingxin Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Shengwei Jiang
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Lizhong Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Kenji Watanabe
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Takashi Taniguchi
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Allan H. MacDonald
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Jie Shan
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Kin Fai Mak
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

Z.T. and B.S. performed the optical and electrical experiments and the analysis with help from W.Z. N.C.H., Z.T. and A.H.M. performed the theoretical analysis. W.Z., B.S., Z.T., T.L., S.J., and L.L. fabricated the device. K.W. and T.T. grew the bulk hBN crystals. Z.T., K.F.M. and J.S. designed the scientific objectives and oversaw the project. All authors discussed the results and commented on the manuscript.

Corresponding authors

Correspondence to Jie Shan or Kin Fai Mak.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Nanotechnology thanks Mingliang Tian, Lan Wang and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Schematic crystal structure and moiré bands in AB-stacked MoTe2/WSe2.

a, Moiré pattern (left) formed in AB-stack MoTe2/WSe2. MM, MX and XX (M = Mo, W; X = Se, Te) are the high-symmetry stacking sites (right). The Wannier orbitals of the two layers occupy the MM and XX sites, forming a honeycomb lattice. An out-of-plane electric field (E) induces the QAH effect. b, Schematic illustration of the electric-field-induced topological phase transition from a charge-transfer insulator (left) to a Chern insulator (right) at \(\nu =1\). Left: The Mo-moiré band is split into the lower and upper Hubbard bands by the on-site energy \(U\). The W-moiré band lies in the Mott gap, resulting in a charge transfer insulator. Right: When the W-moiré band is pushed up by the electric field, band inversion occurs and the Chern insulator emerges.

Extended Data Fig. 2 Basic characterization for the Chern insulator.

a, Magnetic-field dependence of \({R}_{{xx}}\) and \({R}_{{xy}}\) at 1.6 K for the Chern insulating state (\({V}_{{tg}}\) = -4.693 V, \({V}_{{bg}}\) = 3.528 V). Nearly quantized \({R}_{{xy}}\) and vanishing \({R}_{{xx}}\) are observed at magnetic fields higher than 0.2 T. b, The corresponding magnetic-field dependent MCD. A hysteresis is observed, consistent with the transport results and with the emergence of a ferromagnetic state.

Extended Data Fig. 3 Zero-bias MCD images at varying fillings and electric fields.

a, b, Zero-bias spontaneous MCD images at varying filling factors and fixed \(E=0.628\) V/nm (a) and at varying electric fields and fixed \(\nu =1\) (b). Temperature is at 1.6 K. Black dashed lines mark the sample boundaries. Strongest MCD is observed at the Chern insulating state (\(\nu =1\) and \(E=0.633\) V/nm); the MCD signal decreases with detuned \(\nu\) and \(E\). MCD inhomogeneity originating from strain and/or twist angle disorders is also observed.

Extended Data Fig. 4 Temperature dependent spontaneous MCD.

Zero-bias spontaneous MCD images at varying temperatures for the Chern insulating state (\({V}_{{tg}}\) = -4.693 V, \({V}_{{bg}}\) = 3.528 V). Spontaneous MCD is observed below about 5 K. Black dashed lines mark the sample boundaries.

Extended Data Fig. 5 Dependence of the SHE on the directions of bias current and spontaneous magnetization.

a, MCD images at 1.6 K under reversed bias current compared to Fig. 2b. Positive spontaneous MCD is prepared at zero bias. The current-induced edge MCD has opposite signs compared to Fig. 2b, consistent with the bulk SHE beyond QAH breakdown. b, MCD images at 1.6 K with spontaneous MCD opposite to that in Fig. 2b. The same current-induced MCD images are observed at high bias, demonstrating that the SHE is independent of the spontaneous magnetization direction.

Extended Data Fig. 6 SHE with currents biased along the short axis.

MCD images at 6 K (a) and 1.6 K (b) under varying bias currents. The bias current is along the short axis near one end of the Hall bar. The current is confined to a small region near the tip of the electrodes. Opposite magnetizations are observed on two sides of the current and the magnitude increases with increasing bias current. The current path, identified from zero MCD, deviates from a straight line due to sample inhomogeneities. Spontaneous MCD is also observed at 1.6 K under zero bias. The spontaneous MCD is quenched beyond the QAH breakdown. The 1.6 K and 6 K MCD images are nearly identical under high bias.

Extended Data Fig. 7 Giant spin accumulation at high bias.

a, Bias current-dependent edge MCD at 1.6 K for the Chern insulating state (at P1 in Fig. 2a). A QAH breakdown is observed near 0.5 µA, where the MCD switches sign. b, The corresponding magnetic field dependent zero-bias MCD at the same sample location. We can see that the current-induced MCD at high bias (a) is as strong as the zero-bias MCD near magnetic saturation at 0.5 T (b). The results demonstrate the giant spin accumulation on sample edges due to the SHE.

Extended Data Fig. 8 Magnetic field dependent QAH breakdown.

a, b, Dependence of \({R}_{{xx}}\) (a) and \({R}_{{xy}}\) (b) on the bias current and magnetic field at 1.6 K for the Chern insulating state. QAH breakdown is marked by rapid changes in both \({R}_{{xx}}\) and \({R}_{{xy}}\) (the dashed lines). The critical current for the QAH breakdown increases with magnetic field. c, Corresponding bias current-dependent edge MCD (at P1 in Fig. 2a) at representative magnetic fields. The MCD switches sign at the QAH breakdown critical current, which increases with magnetic field, consistent with the transport results.

Extended Data Fig. 9 SHE with different bias current path.

MCD images at 1.6 K and \(\nu =1\) using different pairs of Hall probes as the source (S) and drain (D). The bias current is shown in each panel. Black dashed lines mark the sample boundaries; and arrows show the bias current direction. Due to the SHE, the sample is split into two domains of opposite MCD according to the bias current path. The current path centerline, where the MCD is zero, deviates from a straight line connecting S and D due to sample inhomogeneity.

Extended Data Fig. 10 Steady state drift-diffusion model in non-local geometry.

a, Schematic sample geometry with half-length \(L\) and width \(W\). The coordinate system is set up such that the sample center is at the origin. Current ejection/extraction points are marked by dark blue disks at \(x=0,{y}=\pm W/2\). b, c, d, Spin density \({n}_{s}\) and spin current density \({J}_{s}\) profile at \(y=0\) for representative spin diffusion lengths with sample geometry \(L=3\mu {m}\) (b), \(9\mu {m}\) (c), \(30\mu {m}\) (d) and fixed \(W=3\mu m\). A Hall angle of \(\pi /6\) is used in all cases. With increasing \(L\), the spin density becomes more localized around the current centerline and the spin current density \({J}_{s}\) shows stronger dependence on the spin diffusion length.

Supplementary information

Supplementary Video 1

Bias-dependent MCD images at 1.6 K.

Supplementary Video 2

Bias-dependent MCD difference between 1.6 and 6 K.

Source data

Source Data Fig. 1

Statistical source data for Fig. 1.

Source Data Fig. 2

Statistical source data for Fig. 2.

Source Data Fig. 3

Statistical source data for Fig. 3.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Tao, Z., Shen, B., Zhao, W. et al. Giant spin Hall effect in AB-stacked MoTe2/WSe2 bilayers. Nat. Nanotechnol. 19, 28–33 (2024). https://doi.org/10.1038/s41565-023-01492-2

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41565-023-01492-2

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing