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.

  • Letter
  • Published:

Odd- and even-denominator fractional quantum Hall states in monolayer WSe2

Abstract

Monolayer semiconducting transition-metal dichalcogenides (TMDs) represent a unique class of two-dimensional (2D) electron systems. Their atomically thin structure facilitates gate tunability just like graphene does, but unlike graphene, TMDs have the advantage of a sizable band gap and strong spin–orbit coupling. Measurements under large magnetic fields have revealed an unusual Landau level (LL) structure1,2,3, distinct from other 2D electron systems. However, owing to the limited sample quality and poor electrical contact, probing the lowest LLs has been challenging, and observation of electron correlations within the fractionally filled LL regime has not been possible. Here, through bulk electronic compressibility measurements, we investigate the LL structure of monolayer WSe2 in the extreme quantum limit, and observe fractional quantum Hall states in the lowest three LLs. The odd-denominator fractional quantum Hall sequences demonstrate a systematic evolution with the LL orbital index, consistent with generic theoretical expectations. In addition, we observe an even-denominator state in the second LL that is expected to host non-Abelian statistics. Our results suggest that the 2D semiconductors can provide an experimental platform that closely resembles idealized theoretical models in the quantum Hall regime.

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

Access options

Buy this article

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

Fig. 1: Measurement scheme and LL structure.
Fig. 2: FQH states.
Fig. 3: Evolution of FQH states with LL orbital index.

Similar content being viewed by others

Data availability

The data that support the plots within this paper and other findings of this study are available at https://doi.org/10.5518/807.

References

  1. Wang, Z., Shan, J. & Mak, K. F. Valley- and spin-polarized Landau levels in monolayer WSe2. Nat. Nanotechnol. 12, 144–149 (2016).

    Google Scholar 

  2. Movva, H. C. P. et al. Density-dependent quantum Hall states and Zeeman splitting in monolayer and bilayer WSe2. Phys. Rev. Lett. 118, 247701 (2017).

    Article  Google Scholar 

  3. Gustafsson, M. V. et al. Ambipolar Landau levels and strong band-selective carrier interactions in monolayer WSe2. Nat. Mater. 17, 411–415 (2018).

    Article  CAS  Google Scholar 

  4. Tsui, D. C., Stormer, H. L. & Gossard, A. C. Two-dimensional magnetotransport in the extreme quantum limit. Phys. Rev. Lett. 48, 1559 (1982).

    Article  CAS  Google Scholar 

  5. Kleinbaum, E., Kumar, A., Pfeiffer, L. N., West, K. W. & Csáthy, G. A. Gap reversal at filling factors 3 + 1/3 and 3 + 1/5: towards novel topological order in the fractional quantum hall regime. Phys. Rev. Lett. 114, 076801 (2015).

    Article  Google Scholar 

  6. Willett, R. et al. Observation of an even-denominator quantum number in the fractional quantum Hall effect. Phys. Rev. Lett. 59, 1776–1779 (1987).

    Article  CAS  Google Scholar 

  7. Falson, J. et al. Even-denominator fractional quantum Hall physics in ZnO. Nat. Phys. 11, 347–351 (2015).

    Article  Google Scholar 

  8. Ki, D.-K., Fal’ko, V. I., Abanin, D. A. & Morpurgo, A. F. Observation of even denominator fractional quantum Hall effect in suspended bilayer graphene. Nano Lett. 14, 2135–2139 (2014).

    Article  CAS  Google Scholar 

  9. Zibrov, A. A. et al. Tunable interacting composite fermion phases in a half-filled bilayer-graphene Landau level. Nature 549, 360–364 (2017).

    Article  CAS  Google Scholar 

  10. Li, J. I. A. et al. Even-denominator fractional quantum Hall states in bilayer graphene. Science 358, 648–652 (2017).

    Article  CAS  Google Scholar 

  11. Moore, G. & Read, N. Nonabelions in the fractional quantum Hall effect. Nuc. Phys. B 360, 362–396 (1991).

    Article  Google Scholar 

  12. Levin, M., Halperin, B. I. & Rosenow, B. Particle-hole symmetry and the Pfaffian state. Phys. Rev. Lett. 99, 236806 (2007).

    Article  Google Scholar 

  13. Lee, S.-S., Ryu, S., Nayak, C. & Fisher, M. P. A. Particle-hole symmetry and the \(\nu =\frac{5}{2}\)quantum Hall state. Phys. Rev. Lett. 99, 236807 (2007).

    Article  Google Scholar 

  14. Son, D. T. Is the composite fermion a dirac particle? Phys. Rev. X 5, 031027 (2015).

    Google Scholar 

  15. Goerbig, M. O. Electronic properties of graphene in a strong magnetic field. Rev. Mod. Phys. 83, 1193–1243 (2011).

    Article  CAS  Google Scholar 

  16. Dean, C. R. et al. Multicomponent fractional quantum Hall effect in graphene. Nat. Phys. 7, 693–696 (2011).

    Article  CAS  Google Scholar 

  17. Feldman, B. E., Krauss, B., Smet, J. H. & Yacoby, A. Unconventional sequence of fractional quantum Hall states in suspended graphene. Science 337, 1196–1199 (2012).

    Article  CAS  Google Scholar 

  18. Zibrov, A. et al. Even-denominator fractional quantum Hall states at an isospin transition in monolayer graphene. Nat. Phys. 14, 930–935 (2018).

    Article  CAS  Google Scholar 

  19. de C. Chamon, C., Freed, D. E., Kivelson, S. A., Sondhi, S. L. & Wen, X. G. Two point-contact interferometer for quantum Hall systems. Phys. Rev. B 55, 2331–2343 (1997).

    Article  Google Scholar 

  20. 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 

  21. Li, X., Zhang, F. & Niu, Q. Unconventional quantum Hall effect and tunable spin Hall effect in Dirac materials: application to an isolated MoS2 trilayer. Phys. Rev. Lett. 110, 066803 (2013).

    Article  Google Scholar 

  22. Rose, F., Goerbig, M. O. & Piéchon, F. Spin- and valley-dependent magneto-optical properties of MoS2. Phys. Rev. B 88, 125438 (2013).

    Article  Google Scholar 

  23. Larentis, S. et al. Large effective mass and interaction-enhanced Zeeman splitting of K-valley electrons in MoSe2. Phys. Rev. B 97, 201407 (2018).

    Article  CAS  Google Scholar 

  24. Pisoni, R. et al. Interactions and magnetotransport through spin-valley coupled Landau levels in monolayer MoS2. Phys. Rev. Lett. 121, 247701 (2018).

    Article  CAS  Google Scholar 

  25. Edelberg, D. et al. Approaching the intrinsic limit in transition metal diselenides via point defect control. Nano Lett. 19, 4371–4379 (2019).

    Article  CAS  Google Scholar 

  26. Eisenstein, J. P., Pfeiffer, L. N. & West, K. W. Compressibility of the two-dimensional electron gas: measurements of the zero-field exchange energy and fractional quantum Hall gap. Phys. Rev. B 50, 1760–1778 (1994).

    Article  CAS  Google Scholar 

  27. Jain, J. K. Composite Fermions (Cambridge University Press, 2007).

  28. Goerbig, M. O. & Smith, C. M. Scaling approach to the phase diagram of quantum Hall systems. Europhys. Lett. 63, 736–742 (2003).

    Article  CAS  Google Scholar 

  29. Goerbig, M. O., Lederer, P. & Smith, C. M. Competition between quantum-liquid and electron-solid phases in intermediate Landau levels. Phys. Rev. B 69, 115327 (2004).

    Article  Google Scholar 

  30. Halperin, B. I. Theory of the quantized Hall conductance. Helv. Phys. Acta 56, 75–102 (1983).

    CAS  Google Scholar 

  31. Pan, W. et al. Exact quantization of the even-denominator fractional quantum Hall state at v=5/2 Landau level filling factor. Phys. Rev. Lett. 83, 3530–3533 (1999).

    Article  CAS  Google Scholar 

  32. Pistunova, K. et al. Transport and photoluminescent characterization of high-quality single layer WSe2 devices. In APS March Meeting 2019 A15.007 (APS, 2019).

  33. Apalkov, V. M. & Chakraborty, T. Stable Pfaffian state in bilayer graphene. Phys. Rev. Lett. 107, 186803 (2011).

    Article  Google Scholar 

  34. Papić, Z., Abanin, D. A., Barlas, Y. & Bhatt, R. N. Tunable interactions and phase transitions in Dirac materials in a magnetic field. Phys. Rev. B 84, 241306 (2011).

    Article  Google Scholar 

  35. Gervais, G. et al. Competition between a fractional quantum Hall liquid and bubble and Wigner crystal phases in the third Landau level. Phys. Rev. Lett. 93, 266804 (2004).

    Article  CAS  Google Scholar 

  36. Zeng, Y. et al. High-quality magnetotransport in graphene using the edge-free Corbino geometry. Phys. Rev. Lett. 122, 137701 (2019).

    Article  CAS  Google Scholar 

  37. Peterson, M. R., Jolicoeur, T. & das Sarma, S. Orbital Landau level dependence of the fractional quantum Hall effect in quasi-two-dimensional electron layers: finite-thickness effects. Phys. Rev. B 78, 155308 (2008).

    Article  Google Scholar 

  38. Sreejith, G. J., Zhang, Y. & Jain, J. K. Surprising robustness of particle-hole symmetry for composite-fermion liquids. Phys. Rev. B 96, 125149 (2017).

    Article  Google Scholar 

Download references

Acknowledgements

We thank M. Goerbig, A. Kormanyos and F. Zhang for discussion, and W. Coniglio and B. Pullum for help with experiments. This research is primarily supported by the US Department of Energy (DE-SC0016703). Synthesis of WSe2 (D.R. and B.K.) was supported by the Center for Precision Assembly of Superstratic and Superatomic Solids, a Materials Science and Engineering Research Center (MRSEC), through NSF grant DMR-1420634. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement no. DMR-1157490 and the state of Florida. Z.P. acknowledges support by EPSRC grant EP/R020612/1. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan and the CREST (JPMJCR15F3), JST.

Author information

Authors and Affiliations

Authors

Contributions

Q.S. fabricated the device with the help of E.S.; M.V.G. contributed to the development of the measurement set-up. Q.S. performed the measurements and analysed the data. Z.P. performed the numerical calculations. D.A.R. and B.K. grew the WSe2 crystals. K.W. and T.T. grew the hBN crystals. J.H. and C.R.D. advised on the experiments. The manuscript was written with input from all authors.

Corresponding author

Correspondence to Cory R. Dean.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Nanotechnology thanks Jinfeng Jia and the other, anonymous, reviewers for their contribution to the peer review of this work.

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

Supplementary information

Supplementary Information

Supplementary discussion, Figs. 1–10 and refs. 1–49.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Shi, Q., Shih, EM., Gustafsson, M.V. et al. Odd- and even-denominator fractional quantum Hall states in monolayer WSe2. Nat. Nanotechnol. 15, 569–573 (2020). https://doi.org/10.1038/s41565-020-0685-6

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41565-020-0685-6

This article is cited by

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