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Giant effective Zeeman splitting in a monolayer semiconductor realized by spin-selective strong light–matter coupling

Abstract

Strong coupling between light and the fundamental excitations of a two-dimensional electron gas (2DEG) is of foundational importance both to pure physics and to the understanding and development of future photonic nanotechnologies1,2,3,4,5,6,7. Here we study the relationship between spin polarization of a 2DEG in a monolayer semiconductor, MoSe2, and light–matter interactions modified by a zero-dimensional optical microcavity. We find pronounced spin-susceptibility of the 2DEG to simultaneously enhance and suppress trion-polariton formation in opposite photon helicities. This leads to observation of a giant effective valley Zeeman splitting for trion-polaritons (g-factor of >20), exceeding the purely trionic splitting by over five times. Going further, we observe clear effective optical nonlinearity arising from the highly nonlinear behaviour of the valley-specific strong light–matter coupling regime, and allowing all-optical tuning of the polaritonic Zeeman splitting from 4 meV to >10 meV. Our experiments lay the groundwork for engineering topological phases with true unidirectionality in monolayer semiconductors, accompanied by giant effective photonic nonlinearities rooted in many-body exciton–electron correlations.

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Fig. 1: Excitations of a 2DEG strongly coupled to light in monolayer MoSe2.
Fig. 2: Giant effective trion-polariton Zeeman splitting.
Fig. 3: Trion-polariton effective nonlinearity.

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Data supporting the plots within this paper are available from the corresponding authors upon request.

References

  1. Smolka, S. et al. Cavity quantum electrodynamics with many-body states of a two-dimensional electron gas. Science 346, 332–335 (2014).

    Article  ADS  Google Scholar 

  2. Efimkin, D. K. & MacDonald, A. H. Many-body theory of trion absorption features in two-dimensional semiconductors. Phys. Rev. B 95, 035417 (2017).

    Article  ADS  Google Scholar 

  3. Back, P. et al. Giant paramagnetism-induced valley polarization of electrons in charge-tunable monolayer MoSe2. Phys. Rev. Lett. 118, 237404 (2017).

    Article  ADS  Google Scholar 

  4. Sidler, M. et al. Fermi polaron-polaritons in charge-tunable atomically thin semiconductors. Nat. Phys. 13, 255–261 (2017).

    Article  Google Scholar 

  5. Tan, L. B. et al. Interacting polaron-polaritons. Phys. Rev. X 10, 021011 (2020).

    Google Scholar 

  6. Klein, J. et al. Controlling exciton many-body states by the electric-field effect in monolayer MoS2. Phys. Rev. Res. 3, L022009 (2021).

    Article  Google Scholar 

  7. Roch, J. G. et al. Spin-polarized electrons in monolayer MoS2. Nat. Nanotechnol. 14, 432–436 (2019).

    Article  ADS  Google Scholar 

  8. Glazov, M. M. Optical properties of charged excitons in two-dimensional semiconductors. J. Chem. Phys. 153, 034703 (2020).

    Article  Google Scholar 

  9. Imamoglu, A., Cotlet, O. & Schmidt, R. Exciton-polarons in two-dimensional semiconductors and the Tavis-Cummings model. C. R. Phys. 22, 89–96 (2021).

    Google Scholar 

  10. MacNeill, D. et al. Breaking of valley degeneracy by magnetic field in monolayer MoSe2. Phys. Rev. Lett. 114, 037401 (2015).

    Article  ADS  Google Scholar 

  11. Langer, F. et al. Lightwave valleytronics in a monolayer of tungsten diselenide. Nature 557, 76–80 (2018).

    Article  ADS  Google Scholar 

  12. Ozawa, T. et al. Topological photonics. Rev. Mod. Phys. 91, 015006 (2019).

    Article  ADS  MathSciNet  Google Scholar 

  13. Li, M. et al. Experimental observation of topological Z2 exciton-polaritons in transition metal dichalcogenide monolayers. Nat. Commun. 12, 4425 (2021).

    Article  ADS  Google Scholar 

  14. Liu, W. et al. Generation of helical topological exciton-polaritons. Science 370, 600–604 (2020).

    Article  MathSciNet  Google Scholar 

  15. Wang, Z., Chong, Y., Joannopoulos, J. D. & Soljačić, M. Observation of unidirectional backscattering-immune topological electromagnetic states. Nature 461, 772–775 (2009).

    Article  ADS  Google Scholar 

  16. Lu, L., Joannopoulos, J. D. & Soljačić, M. Topological photonics. Nat. Photon. 8, 821–829 (2014).

    Article  ADS  Google Scholar 

  17. Bahari, B. et al. Nonreciprocal lasing in topological cavities of arbitrary geometries. Science 358, 636–640 (2017).

    Article  ADS  Google Scholar 

  18. Nalitov, A. V., Solnyshkov, D. D. & Malpuech, G. Polariton Z topological insulator. Phys. Rev. Lett. 114, 116401 (2015).

    Article  ADS  MathSciNet  Google Scholar 

  19. Klembt, S. et al. Exciton-polariton topological insulator. Nature 562, 552–556 (2018).

    Article  ADS  Google Scholar 

  20. Song, W. et al. Breakup and recovery of topological zero modes in finite non-Hermitian optical lattices. Phys. Rev. Lett. 123, 165701 (2019).

    Article  ADS  Google Scholar 

  21. Emmanuele, R. P. A. et al. Highly nonlinear trion-polaritons in a monolayer semiconductor. Nat. Commun. 11, 3589 (2020).

    Article  ADS  Google Scholar 

  22. Keller, J. et al. Controlling the magneto-transport properties of EuS thin films. IEEE Trans. Magn. 38, 2673–2675 (2002).

    Article  ADS  Google Scholar 

  23. Grzeszczyk, M. et al. The effect of metallic substrates on the optical properties of monolayer MoSe2. Sci. Rep. 10, 4981 (2020).

    Article  ADS  Google Scholar 

  24. Roch, J. G. et al. First-order magnetic phase transition of mobile electrons in monolayer MoS2. Phys. Rev. Lett. 124, 187602 (2020).

    Article  ADS  Google Scholar 

  25. Lyons, T. P. et al. Interplay between spin proximity effect and charge-dependent exciton dynamics in MoSe2/CrBr3 van der Waals heterostructures. Nat. Commun. 11, 6021 (2020).

    Article  ADS  Google Scholar 

  26. Dufferwiel, S. et al. Valley-addressable polaritons in atomically thin semiconductors. Nat. Photon. 11, 497–501 (2017).

    Article  Google Scholar 

  27. Lundt, N. et al. Magnetic-field-induced splitting and polarization of monolayer-based valley exciton polaritons. Phys. Rev. B 100, 121303(R) (2019).

    Article  ADS  Google Scholar 

  28. Glazov, M. M. et al. Exciton fine structure and spin decoherence in monolayers of transition metal dichalcogenides. Phys. Rev. B 89, 201302(R) (2014).

    Article  ADS  Google Scholar 

  29. Amo, A. et al. Exciton-polariton spin switches. Nat. Photon. 4, 361–366 (2010).

    Article  ADS  Google Scholar 

  30. Smirnova, D., Leykam, D., Chong, Y. & Kivshar, Y. Nonlinear topological photonics. Appl. Phys. Rev. 7, 021306 (2020).

    Article  ADS  Google Scholar 

Download references

Acknowledgements

T.P.L. acknowledges financial support from the EPSRC Doctoral Prize Fellowship scheme (grant reference EP/R513313/1) and the JSPS Postdoctoral Fellowships for Research in Japan scheme. T.P.L., D.J.G., J.P., Y.O. and A.I.T. acknowledge support from the Royal Society International Exchange (grant no. IEC\R3\170088). T.P.L., D.J.G., A.G., C. Louca, L.K., I.A., M.B. and A.I.T. acknowledge support from an EPSRC Centre-to-Centre grant (no. EP/S030751/1). T.P.L., D.J.G. and A.I.T. additionally acknowledge financial support from the European Graphene Flagship Project (grant agreement no. 881603) and EPSRC (grants nos. EP/V006975/1, EP/P026850/1 and EP/V026496/1). C. Leblanc, D.S. and G.M. acknowledge support from projects EU ‘TOPOLIGHT’ (964770) and ‘QUANTOPOL’ (846353), from ANR Labex GaNEXT (ANR-11-LABX-0014) and the ANR programme ‘Investissements d’Avenir’ through the IDEX-ISITE initiative 16-IDEX-0001 (CAP 20-25). L.K., I.A. and M.B. acknowledge financial support from the Deutsche Forschungsgemeinschaft through the International Collaborative Research Centre 160 (project no. C2) and a UAR professorship, Mercur Foundation (grant no. Pe-2019-0022). We thank D. N. Krizhanovskii for useful discussions.

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T.P.L., D.J.G. and J.P. performed low-temperature magneto-optical spectroscopy. T.P.L., D.J.G., C. Leblanc, D.D.S., G.M. and A.I.T. analysed and discussed the bare flake and cavity spectroscopy data. C. Leblanc, D.D.S. and G.M. developed the cavity fitting model and rate equations. L.K. and I.A.A. collected and analysed time-resolved data. J.P. and P.M. deposited the EuS films onto DBR substrates. T.P.L., D.J.G., J.P. and P.M. performed SQUID magnetometry. C. Louca identified and transferred MoSe2 flakes onto EuS films. A.G. carried out electron density calculations. M.B., Y.O., G.M. and A.I.T. managed various aspects of the project. A.I.T. supervised the project. T.P.L. wrote the manuscript, with contributions from all co-authors.

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Correspondence to T. P. Lyons or A. I. Tartakovskii.

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Nature Photonics thanks Anton Nalitov and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Lyons, T.P., Gillard, D.J., Leblanc, C. et al. Giant effective Zeeman splitting in a monolayer semiconductor realized by spin-selective strong light–matter coupling. Nat. Photon. 16, 632–636 (2022). https://doi.org/10.1038/s41566-022-01025-8

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