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Ultrafast switching of trions in 2D materials by terahertz photons

Nature Photonics (2024)Cite this article

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Abstract

External control of optical excitations is key for manipulating light–matter coupling and is highly desirable for photonic technologies. Excitons in monolayer semiconductors emerged as a unique nanoscale platform in this context, offering strong light–matter coupling, spin–valley locking and exceptional tunability. Crucially, they allow electrical switching of their optical response due to efficient interactions of excitonic emitters with free charge carriers, forming new quasiparticles known as trions and Fermi polarons. However, there are major limitations to how fast the light emission of these states can be tuned, restricting the majority of applications to an essentially static regime. Here we demonstrate switching of excitonic light emitters in monolayer semiconductors on ultrafast picosecond time scales by applying short pulses in the terahertz spectral range following optical injection. The process is based on a rapid conversion of trions to excitons by absorption of terahertz photons inducing photodetachment. Monitoring time-resolved emission dynamics in optical-pump/terahertz-push experiments, we achieve the required resonance conditions as well as demonstrate tunability of the process with delay time and terahertz pulse power. Our results introduce a versatile experimental tool for fundamental research of light-emitting excitations of composite Bose–Fermi mixtures and open up pathways towards technological developments of new types of nanophotonic device based on atomically thin materials.

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Fig. 1: Impact of strong terahertz radiation on the exciton–electron complexes in monolayer MoSe2.
Fig. 2: Resonance conditions for the terahertz-induced trion-to-exciton conversion.
Fig. 3: Tunability of the trion-to-exciton conversion with delay time and terahertz fluence.

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Data availability

The data used in this study are available from the corresponding authors upon reasonable request and in the figshare repository at https://doi.org/10.6084/m9.figshare.26244017 (ref. 48).

Code availability

The codes that support the plots and data analysis within this paper are available from the corresponding author upon reasonable request and in the figshare repository at https://doi.org/10.6084/m9.figshare.26244017 (ref. 48).

References

  1. Haug, H. & Koch, S. W. Quantum Theory of the Optical and Electronic Properties of Semiconductors 5th edn (World Scientific, 2009).

  2. Byrnes, T., Kim, N. Y. & Yamamoto, Y. Exciton-polariton condensates. Nat. Phys. 10, 803–813 (2014).

    Article  Google Scholar 

  3. Basov, D. N., Fogler, M. M. & García de Abajo, F. J. Polaritons in van der Waals materials. Science 354, 195 (2016).

    Article  Google Scholar 

  4. Kavokin, A. et al. Polariton condensates for classical and quantum computing. Nat. Rev. Phys. 4, 435–451 (2022).

    Article  Google Scholar 

  5. Liu, X. et al. Strong light-matter coupling in two-dimensional atomic crystals. Nat. Photonics 9, 30–34 (2014).

    Article  ADS  Google Scholar 

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

    Article  Google Scholar 

  7. Lundt, N. et al. Optical valley Hall effect for highly valley-coherent exciton-polaritons in an atomically thin semiconductor. Nat. Nanotechnol. 14, 770–775 (2019).

    Article  ADS  Google Scholar 

  8. Wang, G. et al. Colloquium: excitons in atomically thin transition metal dichalcogenides. Rev. Mod. Phys. 90, 021001 (2018).

    Article  ADS  MathSciNet  Google Scholar 

  9. Dufferwiel, S. et al. Exciton-polaritons in van der Waals heterostructures embedded in tunable microcavities. Nat. Commun. 6, 8579 (2015).

    Article  ADS  Google Scholar 

  10. Lundt, N. et al. Room-temperature Tamm-plasmon exciton-polaritons with a WSe2 monolayer. Nat. Commun. 7, 13328 (2016).

  11. Ross, J. S. et al. Electrical control of neutral and charged excitons in a monolayer semiconductor. Nat. Commun. 4, 1474 (2013).

    Article  ADS  Google Scholar 

  12. Smoleński, T. et al. Interaction-induced Shubnikov-de Haas oscillations in optical conductivity of monolayer MoSe2. Phys. Rev. Lett. 123, 097403 (2019).

    Article  ADS  Google Scholar 

  13. Esser, A., Zimmermann, R. & Runge, E. Theory of trion spectra in semiconductor nanostructures. Phys. Status Solidi B 227, 317–330 (2001).

    Article  ADS  Google Scholar 

  14. Mak, K. F., He, K., Shan, J. & Heinz, T. F. Control of valley polarization in monolayer MoS2 by optical helicity. Nat. Nanotechnol. 7, 494–498 (2012).

    Article  ADS  Google Scholar 

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

    Article  Google Scholar 

  16. Rapaport, R., Cohen, E., Ron, A., Linder, E. & Pfeiffer, L. Negatively charged polaritons in a semiconductor microcavity. Phy. Rev. B 63, 1–8 (2001).

    Article  Google Scholar 

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

    Article  ADS  Google Scholar 

  18. Kyriienko, O., Krizhanovskii, D. N. & Shelykh, I. A. Nonlinear quantum optics with trion polaritons in 2D monolayers: conventional and unconventional photon blockade. Phys. Rev. Lett. 125, 197402 (2020).

    Article  ADS  Google Scholar 

  19. Cheng, G., Li, B., Jin, Z., Zhang, M. & Wang, J. Observation of diffusion and drift of the negative trions in monolayer WS2. Nano Lett. 21, 6314–6320 (2021).

    Article  ADS  Google Scholar 

  20. Klein, J. et al. Stark effect spectroscopy of mono- and few-layer MoS2. Nano Lett. 16, 1554–1559 (2016).

    Article  ADS  Google Scholar 

  21. Liu, Y., Huang, Y. & Duan, X. Van der Waals integration before and beyond two-dimensional materials. Nature 567, 323–333 (2019).

    Article  ADS  Google Scholar 

  22. Li, N. et al. Gate-tunable large-scale flexible monolayer MoS2 devices for photodetectors and optoelectronic synapses. Nano Res. 15, 5418–5424 (2022).

    Article  ADS  Google Scholar 

  23. Tongay, S. et al. Defects activated photoluminescence in two-dimensional semiconductors: interplay between bound, charged, and free excitons. Sci. Rep. 3, 2657 (2013).

    Article  Google Scholar 

  24. Kwak, D., Paur, M., Watanabe, K., Taniguchi, T. & Mueller, T. High-speed electroluminescence modulation in monolayer WS2. Adv. Mater. Technol. 7, 2100915 (2022).

    Article  Google Scholar 

  25. Leinß, S. et al. Terahertz coherent control of optically dark paraexcitons in Cu2O. Phys. Rev. Lett. 101, 246401 (2008).

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  27. Yong, C.-K. et al. Valley-dependent exciton fine structure and Autler–Townes doublets from Berry phases in monolayer MoSe2. Nat. Mater. 18, 1065–1070 (2019).

    Article  ADS  Google Scholar 

  28. Sie, E. J. et al. Large, valley-exclusive Bloch–Siegert shift in monolayer WS2. Science 355, 1066–1069 (2017).

    Article  ADS  Google Scholar 

  29. Poellmann, C. et al. Resonant internal quantum transitions and femtosecond radiative decay of excitons in monolayer WSe2. Nat. Mater. 14, 889–893 (2015).

    Article  ADS  Google Scholar 

  30. Venanzi, T. et al. Terahertz-induced energy transfer from hot carriers to trions in a MoSe2 monolayer. ACS Photonics 8, 2931–2939 (2021).

    Article  Google Scholar 

  31. Helm, M. et al. The ELBE infrared and THz facility at Helmholtz-Zentrum Dresden-Rossendorf. Eur. Phys. J. Plus 138, 158 (2023).

    Article  Google Scholar 

  32. Rhodes, D., Chae, S. H., Ribeiro-Palau, R. & Hone, J. Disorder in van der Waals heterostructures of 2D materials. Nat. Mater. 18, 541–549 (2019).

    Article  ADS  Google Scholar 

  33. Raja, A. et al. Dielectric disorder in two-dimensional materials. Nat. Nanotechnol. 14, 832–837 (2019).

    Article  ADS  Google Scholar 

  34. Fang, H. H. et al. Control of the exciton radiative lifetime in van der Waals heterostructures. Phys. Rev. Lett. 123, 067401 (2019).

    Article  ADS  Google Scholar 

  35. Zipfel, J. et al. Electron recoil effect in electrically tunable MoSe2 monolayers. Phys. Rev. B 105, 075311 (2022).

    Article  ADS  Google Scholar 

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

    Article  Google Scholar 

  37. Zybell, S. et al. Photoluminescence dynamics in GaAs/AlGaAs quantum wells under pulsed intersubband excitation. Appl. Phys. Lett. 99, 041103 (2011).

    Article  ADS  Google Scholar 

  38. Rice, W. D. et al. Observation of forbidden exciton transitions mediated by Coulomb interactions in photoexcited semiconductor quantum wells. Phys. Rev. Lett. 110, 137404 (2013).

    Article  ADS  Google Scholar 

  39. Perea-Causin, R., Brem, S. & Malic, E. Trion–phonon interaction in atomically thin semiconductors. Phys. Rev. B 106, 115407 (2022).

    Article  ADS  Google Scholar 

  40. Fey, C., Schmelcher, P., Imamoglu, A. & Schmidt, R. Theory of exciton–electron scattering in atomically thin semiconductors. Phys. Rev. B 101, 195417 (2020).

    Article  ADS  Google Scholar 

  41. Schirotzek, A., Wu, C.-H., Sommer, A. & Zwierlein, M. W. Observation of Fermi polarons in a tunable Fermi liquid of ultracold atoms. Phys. Rev. Lett. 102, 230402 (2009).

    Article  ADS  Google Scholar 

  42. Perea-Causin, R., Brem, S., Schmidt, O. & Malic, E. Trion photoluminescence and trion stability in atomically thin semiconductors. Phys. Rev. Lett. 132, 036903 (2024).

    Article  ADS  Google Scholar 

  43. Esser, A., Runge, E., Zimmermann, R. & Langbein, W. Trions in GaAs quantum wells: photoluminescence lineshape analysis. Phys. Status Solidi A 178, 489–494 (2000).

    Article  ADS  Google Scholar 

  44. Smith, S. J. & Burch, D. S. Photodetachment cross section of the negative hydrogen ion. Phys. Rev. Lett. 2, 165 (1959).

    Article  ADS  Google Scholar 

  45. Castellanos-Gomez, A. et al. Deterministic transfer of two-dimensional materials by all-dry viscoelastic stamping. 2D Mater. 1, 1–20 (2014).

    Article  Google Scholar 

  46. Chandrasekhar, S. Some remarks on the negative hydrogen ion and its absorption coefficient. Astrophys. J. 100, 176–180 (1944).

    Article  ADS  Google Scholar 

  47. Berkelbach, T. C., Hybertsen, M. S. & Reichman, D. R. Theory of neutral and charged excitons in monolayer transition metal dichalcogenides. Phys. Rev. B 88, 045318 (2013).

    Article  ADS  Google Scholar 

  48. Venanzi, T. et al. Ultrafast switching of trion emitters in 2D materials. figshare https://doi.org/10.6084/m9.figshare.26244017 (2024).

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Acknowledgements

We thank M. M. Glazov, M. Ortolani and L. Baldassarre for helpful discussions. Financial support by the DFG via Emmy Noether Initiative (CH 1672/1, project ID 287022282, A.C.), SFB 1277 (project B05, project ID: 314695032, A.C.) and SFB1083 (project B09, project ID 223848855, E.M.), DFG project ‘Propagation dynamics of exciton–electron complexes in atomically-thin semiconductors’ (project ID 542873285, E.M., A.C.), the Würzburg-Dresden Cluster of Excellence on Complexity and Topology in Quantum Matter (ct.qmat) (EXC 2147, project ID 390858490, A.C.) is gratefully acknowledged. Parts of this research were carried out at ELBE at the Helmholtz-Zentrum Dresden-Rossendorf e.V., a member of the Helmholtz Association. We thank P. Michel and the ELBE team for support. A.C. acknowledges funding from ERC through CoG CoulENGINE (GA number 101001764). K.W. and T.T. acknowledge support from the JSPS KAKENHI (grant numbers 20H00354, 21H05233 and 23H02052) and World Premier International Research Center Initiative (WPI), MEXT, Japan.

Author information

Author notes

  1. These authors contributed equally: Tommaso Venanzi, Marzia Cuccu.

Authors and Affiliations

  1. Center for Life Nanoscience, Istituto Italiano di Tecnologia, Rome, Italy

    Tommaso Venanzi

  2. Institute of Applied Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, TUD Dresden University of Technology, Dresden, Germany

    Marzia Cuccu, Manfred Helm & Alexey Chernikov

  3. Department of Physics, Stockholm University, Stockholm, Sweden

    Raul Perea-Causin

  4. Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany

    Xiaoxiao Sun, Manfred Helm & Stephan Winnerl

  5. Department of Physics, Philipps-Universität Marburg, Marburg, Germany

    Samuel Brem, Daniel Erkensten & Ermin Malic

  6. Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan

    Takashi Taniguchi

  7. Research Center for Electronic and Optical Materials, National Institute for Materials Science, Tsukuba, Japan

    Kenji Watanabe

  8. Institute of Applied Physics, TUD Dresden University of Technology, Dresden, Germany

    Manfred Helm

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Contributions

T.V., M.C., S.W. and A.C. conceived the experimental idea with input from M.H. and X.S. T.V. and M.C., contributing equally to this work and supported by X.S., designed the experiment, carried out the measurements and analysed the data. M.C. prepared and characterized the samples using hBN crystals provided by T.T. and K.W., R.P.-C., S.B., D.E. and E.M. performed theoretical calculations. The manuscript was written by T.V., M.C. and A.C. with input from all authors.

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Correspondence to Stephan Winnerl or Alexey Chernikov.

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Venanzi, T., Cuccu, M., Perea-Causin, R. et al. Ultrafast switching of trions in 2D materials by terahertz photons. Nat. Photon. (2024). https://doi.org/10.1038/s41566-024-01512-0

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