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Excitons bound by photon exchange

Nature Physics volume 17, pages 31–35 (2021)Cite this article

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Abstract

In contrast to interband excitons in undoped quantum wells, doped quantum wells do not display sharp resonances due to excitonic bound states. The effective Coulomb interaction between electrons and holes in these systems typically leads to only a depolarization shift of the single-electron intersubband transitions1. Non-perturbative light–matter interaction in solid-state devices has been investigated as a pathway to tuning optoelectronic properties of materials2,3. A recent theoretical work4 predicted that when the doped quantum wells are embedded in a photonic cavity, emission–reabsorption processes of cavity photons can generate an effective attractive interaction that binds electrons and holes together, leading to the creation of an intraband bound exciton. Here, we spectroscopically observe such a bound state as a discrete resonance that appears below the ionization threshold only when the coupling between light and matter is increased above a critical value. Our result demonstrates that two charged particles can be bound by the exchange of transverse photons. Light–matter coupling can thus be used as a tool in quantum material engineering, tuning electronic properties of semiconductor heterostructures beyond those permitted by mere crystal structures, with direct applications to mid-infrared optoelectronics.

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Fig. 1: Coulomb effect in doped and undoped quantum wells.
Fig. 2: Schematics of the experimental set-up.
Fig. 3: Bound-to-continuum nature of the optical transition in bare QWs with no surrounding photonic resonator.
Fig. 4: Experimental reflectivity data.
Fig. 5: Calculation of P.

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Data availability

The data that support the findings of this study are available from the corresponding authors on reasonable request. Source data are provided with this paper.

Code availability

The codes that support the findings of this study are available from the corresponding author (S.D.L.) on reasonable request.

References

  1. Nikonov, D. E., Imamoğlu, A., Butov, L. V. & Schmidt, H. Collective intersubband excitations in quantum wells: Coulomb interaction versus subband dispersion. Phys. Rev. Lett. 79, 4633–4636 (1997).

    Article  ADS  Google Scholar 

  2. Frisk Kockum, A., Miranowicz, A., De Liberato, S., Savasta, S. & Nori, F. Ultrastrong coupling between light and matter. Nat. Rev. Phys. 1, 19–40 (2019).

    Article  Google Scholar 

  3. Forn-Díaz, P., Lamata, L., Rico, E., Kono, J. & Solano, E. Ultrastrong coupling regimes of light-matter interaction. Rev. Mod. Phys. 91, 025005 (2019).

    Article  ADS  Google Scholar 

  4. Cortese, E., Carusotto, I., Colombelli, R. & De Liberato, S. Strong coupling of ionizing transitions. Optica 6, 354–361 (2019).

    Article  ADS  Google Scholar 

  5. Ballarini, D. & De Liberato, S. Polaritonics: from microcavities to sub-wavelength confinement. Nanophotonics 8, 641–654 (2019).

    Article  Google Scholar 

  6. Khurgin, J. Excitonic radius in the cavity polariton in the regime of very strong coupling. Solid State Commun. 117, 307–310 (2001).

    Article  ADS  Google Scholar 

  7. Citrin, D. S. & Khurgin, J. B. Microcavity effect on the electron-hole relative motion in semiconductor quantum wells. Phys. Rev. B 68, 205325 (2003).

    Article  ADS  Google Scholar 

  8. Khurgin, J. B. Pliable polaritons: Wannier exciton-plasmon coupling in metal-semiconductor structures. Nanophotonics 8, 629–639 (2018).

    Article  Google Scholar 

  9. Yang, M.-J., Kim, N. Y., Yamamoto, Y. & Na, N. Verification of very strong coupling in a semiconductor optical microcavity. N. J. Phys. 17, 023064 (2015).

    Article  Google Scholar 

  10. Brodbeck, S. et al. Experimental verification of the very strong coupling regime in a GaAs quantum well microcavity. Phys. Rev. Lett. 119, 027401 (2017).

    Article  ADS  Google Scholar 

  11. Anappara, A. A. et al. Signatures of the ultrastrong light-matter coupling regime. Phys. Rev. B 79, 201303 (2009).

    Article  ADS  Google Scholar 

  12. Todorov, Y. et al. Ultrastrong light-matter coupling regime with polariton dots. Phys. Rev. Lett. 105, 196402 (2010).

    Article  ADS  Google Scholar 

  13. Günter, G. et al. Sub-cycle switch-on of ultrastrong light–matter interaction. Nature 458, 178–181 (2009).

    Article  ADS  Google Scholar 

  14. Levinsen, J., Li, G. & Parish, M. M. Microscopic description of exciton-polaritons in microcavities. Phys. Rev. Res. 1, 033120 (2019).

    Article  Google Scholar 

  15. Averkiev, N. S. & Glazov, M. M. Light-matter interaction in doped microcavities. Phys. Rev. B 76, 045320 (2007).

    Article  ADS  Google Scholar 

  16. Haken, H. Quantum Field Theory of Solids: An Introduction (North-Holland, 1976).

  17. Cooper, L. N. Bound electron pairs in a degenerate fermi gas. Phys. Rev. 104, 1189–1190 (1956).

    Article  ADS  Google Scholar 

  18. Todorov, Y. et al. Optical properties of metal-dielectric-metal microcavities in the thz frequency range. Opt. Express 18, 13886–13907 (2010).

    Article  ADS  Google Scholar 

  19. Dini, D., Köhler, R., Tredicucci, A., Biasiol, G. & Sorba, L. Microcavity polariton splitting of intersubband transitions. Phys. Rev. Lett. 90, 116401 (2003).

    Article  ADS  Google Scholar 

  20. Manceau, J.-M. et al. Resonant intersubband polariton-lo phonon scattering in an optically pumped polaritonic device. Appl. Phys. Lett. 112, 191106 (2018).

    Article  ADS  Google Scholar 

  21. Hopfield, J. Theory of the contribution of excitons to the complex dielectric constant of crystals. Phys. Rev. 112, 1555–1567 (1958).

    Article  ADS  Google Scholar 

  22. De Liberato, S. & Ciuti, C. Quantum theory of electron tunneling into intersubband cavity polariton states. Phys. Rev. B 79, 075317 (2009).

    Article  ADS  Google Scholar 

  23. Vigneron, P.-B. et al. Quantum well infrared photo-detectors operating in the strong light-matter coupling regime. Appl. Phys. Lett. 114, 131104 (2019).

    Article  ADS  Google Scholar 

  24. Galego, J., Garcia-Vidal, F. J. & Feist, J. Cavity-induced modifications of molecular structure in the strong-coupling regime. Phys. Rev. X 5, 041022 (2015).

    Google Scholar 

  25. Ebbesen, T. W. Hybrid light–matter states in a molecular and material science perspective. Acc. Chem. Res. 49, 2403–2412 (2016).

    Article  Google Scholar 

  26. Ruggenthaler, M., Tancogne-Dejean, N., Flick, J., Appel, H. & Rubio, A. From a quantum-electrodynamical light–matter description to novel spectroscopies. Nat. Rev. Chem. 2, 1–16 (2018).

    Article  Google Scholar 

  27. Laussy, F. P., Kavokin, A. V. & Shelykh, I. A. Exciton-polariton mediated superconductivity. Phys. Rev. Lett. 104, 106402 (2010).

    Article  ADS  Google Scholar 

  28. Schlawin, F., Cavalleri, A. & Jaksch, D. Cavity-mediated electron-photon superconductivity. Phys. Rev. Lett. 122, 133602 (2019).

    Article  ADS  Google Scholar 

  29. Curtis, J. B., Raines, Z. M., Allocca, A. A., Hafezi, M. & Galitski, V. M. Cavity quantum eliashberg enhancement of superconductivity. Phys. Rev. Lett. 122, 167002 (2019).

    Article  ADS  Google Scholar 

  30. Thomas, A. et al. Exploring superconductivity under strong coupling with the vacuum electromagnetic field. Preprint at http://arXiv.org/abs/1911.01459v1 (2019).

  31. Capasso, F. et al. Observation of an electronic bound state above a potential well. Nature 358, 565–567 (1992).

    Article  ADS  Google Scholar 

  32. Chassagneux, Y. et al. Electrically pumped photonic-crystal terahertz lasers controlled by boundary conditions. Nature 457, 174–178 (2009).

    Article  ADS  Google Scholar 

Download references

Acknowledgements

S.D.L. is a Royal Society Research Fellow and was partly funded by the Philip Leverhulme Prize of the Leverhulme Trust. R.C., J.M.-M., G.B. and I.C. were partly funded by the European Union FET-Open Grant Number MIR-BOSE 737017. R.C. and A.B. were partly funded by the French National Research Agency (project IRENA). This work was partly supported by the French RENATECH network.

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Author notes

  1. These authors contributed equally to this work. Erika Cortese, Ngoc-Linh Tran.

Authors and Affiliations

  1. School of Physics and Astronomy, University of Southampton, Southampton, UK

    Erika Cortese & Simone De Liberato

  2. Centre de Nanosciences et de Nanotechnologies (C2N), CNRS UMR 9001, Université Paris-Saclay, Palaiseau, France

    Ngoc-Linh Tran, Jean-Michel Manceau, Adel Bousseksou & Raffaele Colombelli

  3. INO-CNR BEC Center and Dipartimento di Fisica, Universita di Trento, Povo, Italy

    Iacopo Carusotto

  4. Laboratorio TASC, CNR-IOM, Trieste, Italy

    Giorgio Biasiol

Authors
  1. Erika Cortese
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  5. Iacopo Carusotto
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  7. Raffaele Colombelli
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  8. Simone De Liberato
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Contributions

S.D.L. supervised the project and led the theoretical work. I.C., R.C. and S.D.L. designed the experiment. R.C. led the experimental work. G.B. grew the sample and N.-L.T fabricated the devices. N.-L.T., J.-M.M. and A.B. carried out the optical characterization. E.C. performed the data analysis. All authors discussed the data and contributed to the manuscript.

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Correspondence to Raffaele Colombelli or Simone De Liberato.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–3 and text.

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Source Data Fig. 3

Source Data for Figure 3.

Source Data Fig. 4

Source Data for Figure 4.

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Cortese, E., Tran, NL., Manceau, JM. et al. Excitons bound by photon exchange. Nat. Phys. 17, 31–35 (2021). https://doi.org/10.1038/s41567-020-0994-6

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