Skip to main content

Thank you for visiting 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.

Giant Rydberg excitons in the copper oxide Cu2O


A highly excited atom having an electron that has moved into a level with large principal quantum number is a hydrogen-like object, termed a Rydberg atom. The giant size of Rydberg atoms1 leads to huge interaction effects. Monitoring these interactions has provided insights into atomic and molecular physics on the single-quantum level. Excitons—the fundamental optical excitations in semiconductors2, consisting of an electron and a positively charged hole—are the condensed-matter analogues of hydrogen. Highly excited excitons with extensions similar to those of Rydberg atoms are of interest because they can be placed and moved in a crystal with high precision using microscopic energy potential landscapes. The interaction of such Rydberg excitons may allow the formation of ordered exciton phases or the sensing of elementary excitations in their surroundings on a quantum level. Here we demonstrate the existence of Rydberg excitons in the copper oxide Cu2O, with principal quantum numbers as large as n = 25. These states have giant wavefunction extensions (that is, the average distance between the electron and the hole) of more than two micrometres, compared to about a nanometre for the ground state. The strong dipole–dipole interaction between such excitons is indicated by a blockade effect in which the presence of one exciton prevents the excitation of another in its vicinity.

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

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: High-resolution absorption spectra of yellow P excitons in Cu2O.
Figure 2: Dependences of experimentally determined parameters of P-exciton lines on principal quantum number n, revealing power-law behaviour.
Figure 3: Reduction of excitonic absorption due to dipole blockade.


  1. Gallagher, T. F. Rydberg atoms. Rep. Prog. Phys. 51, 143–188 (1988)

    ADS  CAS  Article  Google Scholar 

  2. Knox, R. S. Theory of Excitons (eds Ehrenreich, H., Seitz, F. & Turnbull, D. ) Solid State Phys. Suppl. Vol. 5 (Academic, 1963)

    Google Scholar 

  3. Gross, E. F. Optical spectrum of excitons in the crystal lattice. Nuovo Cimento Suppl. 3, 672–701 (1956)

    CAS  Article  Google Scholar 

  4. Gross, E. F. & Karryjew, I. A. The optical spectrum of the exciton. Dokl. Akad. Nauk. SSSR 84, 471–474 (1952)

    CAS  Google Scholar 

  5. Elliott, R. J. Intensity of optical absorption by excitons. Phys. Rev. 108, 1384–1389 (1957)

    ADS  CAS  Article  Google Scholar 

  6. Matsumoto, H., Saito, K., Hasuo, M., Kono, S. & Nagasawa, N. Revived interest on yellow-exciton series in Cu2O: an experimental aspect. Solid State Commun. 97, 125–129 (1996)

    ADS  CAS  Article  Google Scholar 

  7. Saffman, M., Walker, T. G. & Mølmer, K. Quantum information with Rydberg atoms. Rev. Mod. Phys. 82, 2313–2363 (2010)

    ADS  CAS  Article  Google Scholar 

  8. Balewski, J. B. et al. Coupling a single electron to a Bose–Einstein condensate. Nature 502, 664–667 (2013)

    ADS  CAS  Article  Google Scholar 

  9. Kavoulakis, G. M., Chang, Y.-C. & Baym, G. Fine structure of excitons in Cu2O. Phys. Rev. B 55, 7593–7599 (1997)

    ADS  CAS  Article  Google Scholar 

  10. Toyozawa, Y. Interband effect of lattice vibrations in the exciton absorption spectra. J. Phys. Chem. Solids 25, 59–71 (1964)

    ADS  CAS  Article  Google Scholar 

  11. Ueno, T. On the contour of the absorption lines in Cu2O. J. Phys. Soc. Jpn 26, 438–446 (1969)

    ADS  CAS  Article  Google Scholar 

  12. Jolk, A. & Klingshirn, C. F. Linear and nonlinear excitonic absorption and photoluminescence spectra in Cu2O: line shape analysis and exciton drift. Phys. Stat. Sol. B 206, 841–850 (1998)

    ADS  CAS  Article  Google Scholar 

  13. Toyozawa, Y. Theory of line-shapes of the exciton absorption bands. Prog. Theor. Phys. 20, 53–81 (1958)

    ADS  CAS  Article  Google Scholar 

  14. Elliott, R. J. Symmetry of excitons in Cu2O. Phys. Rev. 124, 340–345 (1961)

    ADS  CAS  Article  Google Scholar 

  15. Stolz, H. et al. Condensation of excitons in Cu2O at ultracold temperatures: experiment and theory. New J. Phys. 14, 105007 (2012)

    ADS  Article  Google Scholar 

  16. Bassani, F. & Rovere, M. Biexciton binding energy in Cu2O. Solid State Commun. 19, 887–890 (1976)

    ADS  CAS  Article  Google Scholar 

  17. Kiffner, M., Park, H., Li, W. & Gallagher, T. F. Dipole-dipole-coupled double-Rydberg molecules. Phys. Rev. A 86, 031401(R) (2012)

    ADS  Article  Google Scholar 

  18. Boisseau, C., Simbotin, I. & Côté, R. Macrodimers: ultralong range Rydberg molecules. Phys. Rev. Lett. 88, 133004 (2002)

    ADS  Article  Google Scholar 

  19. Bendkowsky, V. et al. Observation of ultralong-range Rydberg molecules. Nature 458, 1005–1008 (2009)

    ADS  CAS  Article  Google Scholar 

  20. Varga, K., Usukura, J. & Suzuki, Y. Second bound state of the positronium molecule and biexcitons. Phys. Rev. Lett. 80, 1876–1879 (1998)

    ADS  CAS  Article  Google Scholar 

  21. Cassidy, D. B. & Mills, A. P., Jr The production of molecular positronium. Nature 449, 195–197 (2007)

    ADS  CAS  Article  Google Scholar 

  22. Friedrich, H. & Wintgen, D. The hydrogen atom in a uniform magnetic field—an example of chaos. Phys. Rep. 183, 37–79 (1989)

    ADS  MathSciNet  CAS  Article  Google Scholar 

Download references


We thank R. Hönig for experimental support with the first measurements. We acknowledge financial support by the Deutsche Forschungsgemeinschaft (BA 1549/18-1 and SFB 652 Strong correlations and collective effects in radiation fields). M.B. acknowledges support from the Russian Ministry of Science and Education (contract number 14.Z50.31.0021).

Author information

Authors and Affiliations



T.K., D.F. and M.B. conceived, designed and carried out the experiments. H.S. and S.S. contributed through the Rydberg blockade model. All authors cooperated in data analysis, discussions and preparation of the manuscript.

Corresponding author

Correspondence to D. Fröhlich.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

This file contains Supplementary Text, Supplementary Figures 1-5, Supplementary Table 1 and Supplementary References. (PDF 452 kb)

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Kazimierczuk, T., Fröhlich, D., Scheel, S. et al. Giant Rydberg excitons in the copper oxide Cu2O. Nature 514, 343–347 (2014).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


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