Letter | Published:

Colossal infrared and terahertz magneto-optical activity in a two-dimensional Dirac material


When two-dimensional electron gases (2DEGs) are exposed to a magnetic field, they resonantly absorb electromagnetic radiation via electronic transitions between Landau levels1. In 2DEGs with a Dirac spectrum, such as graphene, theory predicts an exceptionally high infrared magneto-absorption, even at zero doping2,3,4,5. However, the measured Landau-level magneto-optical effects in graphene have been much weaker than expected2,6,7,8,9,10,11,12 because of imperfections in the samples available for such experiments. Here, we measure magneto-transmission and Faraday rotation in high-mobility encapsulated monolayer graphene using a custom-designed set-up for magneto-infrared microspectroscopy. Our results show strongly enhanced magneto-optical activity in the infrared and terahertz ranges, characterized by absorption of light near to the 50% maximum allowed, 100% magnetic circular dichroism and high Faraday rotation. Considering that sizeable effects have been already observed at routinely achievable magnetic fields, our findings demonstrate the potential of magnetic tuning in 2D Dirac materials for long-wavelength optoelectronics and plasmonics.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Code availability

All relevant calculation codes are available from the corresponding author upon reasonable request.


  1. 1.

    Poulter, A. J. L. et al. Magneto infrared absorption in high electron density GaAs quantum wells. Phys. Rev. Lett. 86, 336–339 (2001).

  2. 2.

    Sadowski, M. L., Martinez, G., Potemski, M., Berger, C. & Heer, W. A. Landau level spectroscopy of ultrathin graphite layers. Phys. Rev. Lett. 97, 266405 (2006).

  3. 3.

    Shon, N. H. & Ando, T. Quantum transport in two-dimensional graphite system. J. Phys. Soc. Jpn 67, 2421–2429 (1998).

  4. 4.

    Gusynin, V. P., Sharapov, S. G. & Carbotte, J. P. Magneto-optical conductivity in graphene. J. Phys. Condens. Matter 19, 026222 (2007).

  5. 5.

    Abergel, D. S. L. & Falko, V. I. Optical and magneto-optical far-infrared properties of bilayer graphene. Phys. Rev. B 75, 155430 (2007).

  6. 6.

    Jiang, Z. et al. Infrared spectroscopy of Landau levels in graphene. Phys. Rev. Lett. 98, 197403 (2007).

  7. 7.

    Orlita, M. et al. Approaching the Dirac point in high-mobility multilayer epitaxial graphene. Phys. Rev. Lett. 101, 267601 (2008).

  8. 8.

    Crassee, I. et al. Multicomponent magneto-optical conductivity of multilayer graphene on SiC. Phys. Rev. B 84, 035103 (2011).

  9. 9.

    Crassee, I. et al. Giant Faraday rotation in single- and multilayer graphene. Nat. Phys. 7, 48–51 (2011).

  10. 10.

    Orlita, M. et al. Carrier scattering from dynamical magnetoconductivity in quasineutral epitaxial graphene. Phys. Rev. Lett. 107, 216603 (2011).

  11. 11.

    Maero, S. et al. Disorder-perturbed Landau levels in high-electron-mobility epitaxial graphene. Phys. Rev. B 90, 195433 (2014).

  12. 12.

    Chen, Z.-G. et al. Observation of an intrinsic bandgap and Landau level renormalization in graphene/boron-nitride heterostructures. Nat. Commun. 5, 4461 (2014).

  13. 13.

    Castro Neto, A. H., Guinea, F., Peres, N. M. R., Novoselov, K. S. & Geim, A. K. The electronic properties of graphene. Rev. Mod. Phys. 81, 109–162 (2009).

  14. 14.

    Mayorov, S. M. et al. Micrometer-scale ballistic transport in encapsulated graphene at room temperature. Nano Lett. 11, 2396–2399 (2011).

  15. 15.

    Faugeras, C. et al. Landau-level spectroscopy of electron–electron interactions in graphene. Phys. Rev. Lett. 114, 126804 (2015).

  16. 16.

    Russell, B. J., Zhou, B., Taniguchi, T., Watanabe, K. & Henriksen, E. A. Many-particle effects in the cyclotron resonance of encapsulated monolayer graphene. Phys. Rev. Lett. 120, 047401 (2018).

  17. 17.

    Briskot, U., Dmitriev, I. A. & Mirlin, A. D. Quantum magneto-oscillations in the ac conductivity of disordered graphene. Phys. Rev. B 87, 195432 (2013).

  18. 18.

    Orlita, M. et al. Classical to quantum crossover of the cyclotron resonance in graphene: a study of the strength of intraband absorption. New J. Phys. 14, 095008 (2012).

  19. 19.

    Poumirol, J.-M. et al. Electrically controlled terahertz magneto-optical phenomena in continuous and patterned graphene. Nat. Comm. 8, 14626 (2017).

  20. 20.

    Levallois, J., Nedoliuk, I. O., Crassee, I. & Kuzmenko, A. B. Magneto-optical Kramers–Kronig analysis. Rev. Sci. Instrum. 86, 033906 (2015).

  21. 21.

    Ikebe, Y. et al. Optical Hall effect in the integer quantum Hall regime. Phys. Rev. Lett. 104, 256802 (2010).

  22. 22.

    Ferreira, A. et al. Faraday effect in graphene enclosed in an optical cavity and the equation of motion method for the study of magneto-optical transport in solids. New J. Phys. 18, 113036 (2016).

  23. 23.

    Ubrig, N. et al. Fabry–Perot enhanced Faraday rotation in graphene. Opt. Express 21, 24736–24741 (2013).

  24. 24.

    Jang, M. S. et al. Tunable large resonant absorption in a midinfrared graphene Salisbury screen. Phys. Rev. B 90, 165409 (2014).

  25. 25.

    Ju, L. et al. Graphene plasmonics for tunable terahertz metamaterials. Nat. Nanotechnol. 6, 630–634 (2011).

  26. 26.

    Tamagnone, M. et al. Magnetoplasmonic enhancement of Faraday rotation in patterned graphene metasurfaces. Phys. Rev. B 97, 241410(R) (2018).

  27. 27.

    Hunt, B. et al. Massive Dirac fermions and hofstadter butterfly in a van der Waals heterostructure. Science 340, 1427–1430 (2013).

  28. 28.

    Yu, G. L. et al. Hierarchy of Hofstadter states and replica quantum Hall ferromagnetism in graphene superlattices. Nat. Phys. 10, 525–529 (2014).

  29. 29.

    Cao, Y. et al. Unconventional superconductivity in magic-angle graphene superlattices. Nature 556, 43–50 (2018).

  30. 30.

    Kawano, Y. Wide-band frequency-tunable terahertz and infrared detection with graphene. Nanotechnology 24, 214004 (2013).

  31. 31.

    Liang, G. et al. Integrated terahertz graphene modulator with 100% modulation depth. ACS Photonics 2, 1559–1566 (2015).

  32. 32.

    Morimoto, T., Hatsugai, Y. & Aoki, H. Cyclotron radiation and emission in graphene. Phys. Rev. B 78, 073406 (2008).

  33. 33.

    Wendler, F. & Malic, M. Towards a tunable graphene-based Landau level laser in the terahertz regime. Sci. Rep. 5, 12646 (2015).

  34. 34.

    Wang, Y., Tokman, M. & Belyanin, A. Continuous-wave lasing between Landau levels in graphene. Phys. Rev. A 91, 033821 (2015).

Download references


This research was supported by the Swiss National Science Foundation and the EU Project Graphene Flagship.

Author information

A.B.K. conceived the experiment. I.O.N. and A.B.K. realized the experimental set-up and performed the experiments. S.H. and A.K.G. provided samples. I.O.N. and A.B.K. wrote the manuscript with input from S.H. and A.K.G. All authors discussed the results.

Correspondence to Alexey B. Kuzmenko.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

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

Supplementary information

Supplementary Information:

Supplementary Figs. 1–10, Supplementary Table 1, Supplementary refs. 1–24.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark
Fig. 1: Interband Landau-level transitions in high-mobility encapsulated graphene.
Fig. 2: Analysis of the interband Landau-level transitions.
Fig. 3: Far-infrared/terahertz magneto-transmission in weakly doped graphene.
Fig. 4: Faraday rotation and magnetic circular dichroism due to polarization-dependent Pauli blocking.