Magnon-assisted tunnelling in van der Waals heterostructures based on CrBr3


Van der Waals heterostructures, which are composed of layered two-dimensional materials, offer a platform to investigate a diverse range of physical phenomena and could be of use in a variety of applications. Heterostructures containing two-dimensional ferromagnets, such as chromium triiodide (CrI3), have recently been reported, which could allow two-dimensional spintronic devices to be developed. Here we study tunnelling through thin ferromagnetic chromium tribromide (CrBr3) barriers that are sandwiched between graphene electrodes. In devices with non-magnetic barriers, conservation of momentum can be relaxed by phonon-assisted tunnelling or by tunnelling through localized states. In contrast, in the devices with ferromagnetic barriers, the major tunnelling mechanisms are the emission of magnons at low temperatures and the scattering of electrons on localized magnetic excitations at temperatures above the Curie temperature. Magnetoresistance in the graphene electrodes further suggests induced spin–orbit coupling and proximity exchange via the ferromagnetic barrier. Tunnelling with magnon emission offers the possibility of spin injection.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Inelastic magnon-assisted tunnelling.
Fig. 2: Effect of conductance on in-plane magnetic field.
Fig. 3: Inter-LL tunnelling.
Fig. 4: Magnetotransport in graphene proximitized with CrBr3.


  1. 1.

    Novoselov, K. S. et al. Electric field effect in atomically thin carbon films. Science 306, 666–669 (2004).

  2. 2.

    Novoselov, K. S. et al. Two-dimensional atomic crystals. Proc. Natl Acad. Sci. USA 102, 10451–10453 (2005).

  3. 3.

    Novoselov, K. S. Nobel Lecture: Graphene: Materials in the flatland. Rev. Mod. Phys. 83, 837–849 (2011).

  4. 4.

    Butler, S. Z. et al. Progress, challenges, and opportunities in two-dimensional materials beyond graphene. ACS Nano 7, 2898–2926 (2013).

  5. 5.

    Neto, A. H. C. & Novoselov, K. New directions in science and technology: two-dimensional crystals. Rep. Progress. Phys. 74, 082501 (2011).

  6. 6.

    Geim, A. K. & Grigorieva, I. V. Van der Waals heterostructures. Nature 499, 419–425 (2013).

  7. 7.

    Novoselov, K. S., Mishchenko, A., Carvalho, A. & Castro Neto, A. H. 2D materials and van der Waals heterostructures. Science 353, aac9439 (2016).

  8. 8.

    Dean, C. et al. Graphene based heterostructures. Solid State Commun. 152, 1275–1282 (2012).

  9. 9.

    Novoselov, K. S. & Neto, A. H. C. Two-dimensional crystals-based heterostructures: materials with tailored properties. Phys. Scr. T146, 014006 (2012).

  10. 10.

    Wang, H., Eyert, V. & Schwingenschlogl, U. Electronic structure and magnetic ordering of the semiconducting chromium trihalides CrCl3, CrBr3, and CrI3. J. Phys. Condens. Matter 23, 116003 (2011).

  11. 11.

    Sachs, B., Wehling, T. O., Novoselov, K. S., Lichtenstein, A. I. & Katsnelson, M. I. Ferromagnetic two-dimensional crystals: Single layers of K2CuF4. Phys. Rev. B 88, 201402 (2013).

  12. 12.

    Zhang, W. B., Qu, Q., Zhua, P. & Lam, C. H. Robust intrinsic ferromagnetism and half semiconductivity in stable two-dimensional single-layer chromium trihalides. J. Mater. Chem. C 3, 12457–12468 (2015).

  13. 13.

    Liu, J. Y., Sun, Q., Kawazoe, Y. & Jena, P. Exfoliating biocompatible ferromagnetic Cr-trihalide monolayers. Phys. Chem. Chem. Phys. 18, 8777–8784 (2016).

  14. 14.

    McGuire, M. A., Dixit, H., Cooper, V. R. & Sales, B. C. Coupling of crystal structure and magnetism in the layered, ferromagnetic insulator CrI3. Chem. Mater. 27, 612–620 (2015).

  15. 15.

    Huang, B. et al. Layer-dependent ferromagnetism in a van der Waals crystal down to the monolayer limit. Nature 546, 270–273 (2017).

  16. 16.

    Klein, D. R. et al. Probing magnetism in 2D van der Waals crystalline insulators via electron tunneling. Science, eaar3617 (2018).

  17. 17.

    Lee, G. H. et al. Electron tunneling through atomically flat and ultrathin hexagonal boron nitride. Appl. Phys. Lett. 99, 243114 (2011).

  18. 18.

    Amet, F. et al. Tunneling spectroscopy of graphene-boron-nitride heterostructures. Phys. Rev. B 85, 073405 (2012).

  19. 19.

    Britnell, L. et al. Electron tunneling through ultrathin boron nitride crystalline barriers. Nano Lett. 12, 1707–1710 (2012).

  20. 20.

    Britnell, L. et al. Field-effect tunneling transistor based on vertical graphene heterostructures. Science 335, 947–950 (2012).

  21. 21.

    Mishchenko, A. et al. Twist-controlled resonant tunnelling in graphene/boron nitride/graphene heterostructures. Nat. Nanotech. 9, 808–813 (2014).

  22. 22.

    Wallbank, J. R. et al. Tuning the valley and chiral quantum state of Dirac electrons in van der Waals heterostructures. Science 353, 575–579 (2016).

  23. 23.

    Vdovin, E. E. et al. Phonon-assisted resonant tunneling of electrons in graphene-boron nitride transistors. Phys. Rev. Lett. 116, 186603 (2016).

  24. 24.

    Jung, S. et al. Vibrational properties of h-BN and h-BN-graphene heterostructures probed by inelastic electron tunneling spectroscopy. Sci. Rep. 5, 16642 (2015).

  25. 25.

    Chandni, U., Watanabe, K., Taniguchi, T. & Eisenstein, J. P. Signatures of phonon and defect-assisted tunneling in planar metal-hexagonal boron nitride-graphene junctions. Nano Lett. 16, 7982–7987 (2016).

  26. 26.

    Chandni, U., Watanabe, K., Taniguchi, T. & Eisenstein, J. P. Evidence for defect-mediated tunneling in hexagonal boron nitride-based junctions. Nano Lett. 15, 7329–7333 (2015).

  27. 27.

    Moodera, J. S., Hao, X., Gibson, G. A. & Meservey, R. Electron-spin polarization in tunnel junctions in zero applied field with ferromagnetic EuS barriers. Phys. Rev. Lett. 61, 637–640 (1988).

  28. 28.

    Santos, T. S. & Moodera, J. S. Observation of spin filtering with a ferromagnetic EuO tunnel barrier. Phys. Rev. B 69, 241203 (2004).

  29. 29.

    Greenaway, M. T. et al. Resonant tunnelling between the chiral Landau states of twisted graphene lattices. Nat. Phys. 11, 1057–1062 (2015).

  30. 30.

    Yu, G. L. et al. Interaction phenomena in graphene seen through quantum capacitance. Proc. Natl Acad. Sci. USA 110, 3282–3286 (2013).

  31. 31.

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

  32. 32.

    Tsui, D. C., Dietz, R. E. & Walker, L. R. Multiple magnon excitation in NiO by electron tunneling. Phys. Rev. Lett. 27, 1729–1732 (1971).

  33. 33.

    Samuelsen, E. J., Silberglitt, R., Shirane, G. & Remeika, J. P. Spin waves in ferromagnetic CrBr3 studied by inelastic neutron scattering. Phys. Rev. B 3, 157–166 (1971).

  34. 34.

    Yelon, W. B. & Silberglitt, R. Renormalization of large-wave-vector magnons in ferromagnetic CrBr3 studied by inelastic neutron scattering: spin-wave correlation effect. Phys. Rev. B 4, 2280–2286 (1971).

  35. 35.

    Irkhin, V. Y., Katanin, A. A. & Katsnelson, M. I. Self-consistent spin-wave theory of layered Heisenberg magnets. Phys. Rev. B 60, 1082–1099 (1999).

  36. 36.

    Ho, J. T. & Litster, J. D. Magnetic equation of state of CrBr3 near critical point. Phys. Rev. Lett. 22, 603–606 (1969).

  37. 37.

    Ghannadzadeh, S. et al. Simultaneous loss of interlayer coherence and long-range magnetism in quasi-two-dimensional PdCrO2. Nat. Commun. 8, 15001 (2017).

  38. 38.

    De Gennes, P. G. & Friedel, J. Anomalies de resistivite dans certains metaus magnettiques. J. Phys. Chem. Solids 4, 71–77 (1958).

  39. 39.

    Haas, C. Spin-disorder scattering and magnetoresistance of magnetic semiconductors. Phys. Rev. 168, 531–538 (1968).

  40. 40.

    Irkhin, V. Y. & Katsnelson, M. I. Current carriers in a quantum 2-dimensional antiferromagnet. J. Phys. Condens. Matter 3, 6439–6453 (1991).

  41. 41.

    Korenblit, I. Y. & Lazarenko, Y. P. Electron–magnon interaction in ferromagnetic semiconductors. Phys. Status Solidi B 71, K107–K110 (1975).

  42. 42.

    Gantmakher, V. F. & Levinson, Y. B. Carrier Scattering in Metals and Semiconductors (North Holland, Amsterdam,1987).

  43. 43.

    Wang, Z. Y., Tang, C., Sachs, R., Barlas, Y. & Shi, J. Proximity-induced ferromagnetism in graphene revealed by the anomalous Hall effect. Phys. Rev. Lett. 114, 016603 (2015).

  44. 44.

    Leutenantsmeyer, J. C., Kaverzin, A. A., Wojtaszek, M. & van Wees, B. J. Proximity induced room temperature ferromagnetism in graphene probed with spin currents. 2D Mater. 4, 014001 (2017).

  45. 45.

    Mendes, J. B. S. et al. Spin-current to charge-current conversion and magnetoresistance in a hybrid structure of graphene and yttrium iron garnet. Phys. Rev. Lett. 115, 226601 (2015).

  46. 46.

    Lee, J. & Fabian, J. Magnetotransport signatures of the proximity exchange and spin–orbit couplings in graphene. Phys. Rev. B 94, 195401 (2016).

  47. 47.

    Asshoff, P. U. et al. Magnetoresistance of vertical Co-graphene-NiFe junctions controlled by charge transfer and proximity-induced spin splitting in graphene. 2D Mater. 4, 031004 (2017).

Download references


This work was supported by the EU Graphene Flagship Program, the European Research Council Synergy Grant Hetero2D, the Royal Society, the Engineering and Physical Research Council (UK) and the US Army Research Office (W911NF-16-1-0279). S.V.M. was supported by RFBR (17-02-01129a) and RAS Presidium Program N4 (task 007-00220-18-00).

Author information

A.M., F.W. and Y.L. manufactured the devices; D.G., Z.W., V.H.G.-M., J.Y. and S.V.M. performed the measurements; M.T.G., O.K., A.I.L. and M.I.K. performed theoretical simulations, I.J.V.-M., A.M., L.E., A.K.G. and K.S.N. initiated and supervised the work, and wrote the manuscript.

Correspondence to K. S. Novoselov or A. Misra.

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 Notes 1–5 and Supplementary Figures 1–8

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Ghazaryan, D., Greenaway, M.T., Wang, Z. et al. Magnon-assisted tunnelling in van der Waals heterostructures based on CrBr3. Nat Electron 1, 344–349 (2018).

Download citation

Further reading