Skip to main content

Thank you for visiting nature.com. 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.

  • Letter
  • Published:

Spin-transfer torque generated by a topological insulator

Nature volume 511, pages 449–451 (2014)Cite this article

Subjects

Abstract

Magnetic devices are a leading contender for the implementation of memory and logic technologies that are non-volatile, that can scale to high density and high speed, and that do not wear out. However, widespread application of magnetic memory and logic devices will require the development of efficient mechanisms for reorienting their magnetization using the least possible current and power1. There has been considerable recent progress in this effort; in particular, it has been discovered that spin–orbit interactions in heavy-metal/ferromagnet bilayers can produce strong current-driven torques on the magnetic layer2,3,4,5,6,7,8,9,10,11, via the spin Hall effect12,13 in the heavy metal or the Rashba–Edelstein effect14,15 in the ferromagnet. In the search for materials to provide even more efficient spin–orbit-induced torques, some proposals16,17,18,19 have suggested topological insulators20,21, which possess a surface state in which the effects of spin–orbit coupling are maximal in the sense that an electron’s spin orientation is fixed relative to its propagation direction. Here we report experiments showing that charge current flowing in-plane in a thin film of the topological insulator bismuth selenide (Bi2Se3) at room temperature can indeed exert a strong spin-transfer torque on an adjacent ferromagnetic permalloy (Ni81Fe19) thin film, with a direction consistent with that expected from the topological surface state. We find that the strength of the torque per unit charge current density in Bi2Se3 is greater than for any source of spin-transfer torque measured so far, even for non-ideal topological insulator films in which the surface states coexist with bulk conduction. Our data suggest that topological insulators could enable very efficient electrical manipulation of magnetic materials at room temperature, for memory and logic applications.

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

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: The mechanism of current-induced spin accumulation in topological insulators and the sample geometry used in the measurement.
Figure 2: ST-FMR measurements of the current-induced torque, with fits.

Similar content being viewed by others

References

  1. Katine, J. A. & Fullerton, E. E. Device implications of spin transfer torques. J. Magn. Magn. Mater. 320, 1217–1226 (2008)

    Article  ADS  CAS  Google Scholar 

  2. Ando, K. et al. Electric manipulation of spin relaxation using the spin Hall effect. Phys. Rev. Lett. 101, 036601 (2008)

    Article  ADS  CAS  PubMed  Google Scholar 

  3. Pi, U. H. et al. Tilting of the spin orientation induced by Rashba effect in ferromagnetic metal layer. Appl. Phys. Lett. 97, 162507 (2010)

    Article  ADS  CAS  Google Scholar 

  4. Liu, L. Q., Moriyama, T., Ralph, D. C. & Buhrman, R. A. Spin-torque ferromagnetic resonance induced by the spin Hall effect. Phys. Rev. Lett. 106, 036601 (2011)

    Article  ADS  CAS  PubMed  Google Scholar 

  5. Miron, I. M. et al. Perpendicular switching of a single ferromagnetic layer induced by in-plane current injection. Nature 476, 189–193 (2011)

    Article  ADS  CAS  PubMed  Google Scholar 

  6. Liu, L. Q. et al. Spin torque switching with the giant spin Hall effect of tantalum. Science 336, 555–558 (2012)

    Article  ADS  CAS  Google Scholar 

  7. Kim, J. et al. Layer thickness dependence of the current-induced effective field vector in Ta|CoFeB|MgO. Nature Mater. 12, 240–245 (2013)

    Article  ADS  CAS  Google Scholar 

  8. Fan, X. et al. Observation of the nonlocal spin-orbital effective field. Nature Commun. 4, 1799 (2013)

    Article  ADS  CAS  Google Scholar 

  9. Garello, K. et al. Symmetry and magnitude of spin-orbit torques in ferromagnetic heterostructures. Nature Nanotechnol. 8, 587–593 (2013)

    Article  ADS  CAS  Google Scholar 

  10. Emori, S., Bauer, U., Ahn, S.-M., Martinez, E. & Beach, G. S. D. Current-driven dynamics of chiral ferromagnetic domain walls. Nature Mater. 12, 611–616 (2013)

    Article  ADS  CAS  Google Scholar 

  11. Ryu, K.-S., Thomas, L., Yang, S.-H. & Parkin, S. S. P. Chiral spin torque at magnetic domain walls. Nature Nanotechnol. 8, 527–533 (2013)

    Article  ADS  CAS  Google Scholar 

  12. Dyakonov, M. I. & Perel, V. I. Current-induced spin orientation of electrons in semiconductors. Phys. Lett. A 35, 459–460 (1971)

    Article  ADS  Google Scholar 

  13. Hirsch, J. E. Spin Hall effect. Phys. Rev. Lett. 83, 1834–1837 (1999)

    Article  ADS  CAS  Google Scholar 

  14. Edelstein, V. M. Spin polarization of conduction electrons induced by electric current in two-dimensional asymmetric electron systems. Solid State Commun. 73, 233–235 (1990)

    Article  ADS  Google Scholar 

  15. Chernyshov, A. et al. Evidence for reversible control of magnetization in a ferromagnetic material by means of spin–orbit magnetic field. Nature Phys. 5, 656–659 (2009)

    Article  ADS  CAS  Google Scholar 

  16. Burkov, A. A. & Hawthorn, D. G. Spin and charge transport on the surface of a topological insulator. Phys. Rev. Lett. 105, 066802 (2010)

    Article  ADS  CAS  PubMed  Google Scholar 

  17. Culcer, D., Hwang, E. H., Stanescu, T. D. & Das Sarma, S. Two-dimensional surface charge transport in topological insulators. Phys. Rev. B 82, 155457 (2010)

    Article  ADS  CAS  Google Scholar 

  18. Pesin, D. & MacDonald, A. H. Spintronics and pseudospintronics in graphene and topological insulators. Nature Mater. 11, 409–416 (2012)

    Article  ADS  CAS  Google Scholar 

  19. Fischer, M. H., Vaezi, A., Manchon, A. & Kim, E.-A. Large spin torque in topological insulator/ferromagnetic metal bilayers. Preprint at http://arxiv.org/abs/1305.1328 (2013)

  20. Fu, L., Kane, C. L. & Mele, E. J. Topological insulators in three dimensions. Phys. Rev. Lett. 98, 106803 (2007)

    Article  ADS  CAS  Google Scholar 

  21. Hasan, M. Z. & Kane, C. L. Topological insulators. Rev. Mod. Phys. 82, 3045–3067 (2010)

    Article  ADS  CAS  Google Scholar 

  22. Tanaka, T. et al. Intrinsic spin Hall effect and orbital Hall effect in 4d and 5d transition metals. Phys. Rev. B 77, 165117 (2008)

    Article  ADS  CAS  Google Scholar 

  23. Niimi, Y. et al. Giant spin Hall effect Induced by skew scattering from bismuth impurities inside thin film CuBi alloys. Phys. Rev. Lett. 109, 156602 (2012)

    Article  ADS  CAS  PubMed  Google Scholar 

  24. Pai, C.-F. et al. Spin transfer torque devices utilizing the giant spin Hall effect of tungsten. Appl. Phys. Lett. 101, 122404 (2012)

    Article  ADS  CAS  Google Scholar 

  25. Yazyev, O. V., Moore, J. E. & Louie, S. G. Spin polarization and transport of surface states in the topological insulators Bi2Se3 and Bi2Te3 from first principles. Phys. Rev. Lett. 105, 266806 (2010)

    Article  ADS  CAS  PubMed  Google Scholar 

  26. Bahramy, M. S. et al. Emergent quantum confinement at topological insulator surfaces. Nature Commun. 3, 1159 (2012)

    Article  ADS  CAS  Google Scholar 

  27. Wray, L. A. et al. A topological insulator surface under strong Coulomb, magnetic and disorder perturbations. Nature Phys. 7, 32–37 (2011)

    Article  ADS  CAS  Google Scholar 

  28. Valla, T., Pan, Z.-H., Gardner, D., Lee, Y. S. & Chu, S. Photoemission spectroscopy of magnetic and nonmagnetic impurities on the surface of the Bi2Se3 topological insulator. Phys. Rev. Lett. 108, 117601 (2012)

    Article  ADS  CAS  PubMed  Google Scholar 

  29. Heinrich, B. et al. Spin pumping at the magnetic insulator (YIG)/normal metal (Au) interfaces. Phys. Rev. Lett. 107, 066604 (2011)

    Article  ADS  CAS  PubMed  Google Scholar 

  30. Fan, Y. et al. Magnetization switching through giant spin-orbit torque in a magnetically doped topological insulator heterostructure. Nature Mater. 13, 699–704 (2014)

  31. Slonczewski, J. C. Current-driven excitation of magnetic multilayers. J. Magn. Magn. Mater. 159, L1–L7 (1996)

    Article  ADS  CAS  Google Scholar 

  32. King, P. D. C. et al. Large tunable Rashba spin splitting of a two-dimensional electron gas in Bi2Se3 . Phys. Rev. Lett. 107, 096802 (2011)

    Article  ADS  CAS  PubMed  Google Scholar 

  33. Manchon, A. & Zhang, S. Theory of nonequilibrium intrinsic spin torque in a single nanomagnet. Phys. Rev. B 78, 212405 (2008)

    Article  ADS  CAS  Google Scholar 

  34. Pesin, D. A. & MacDonald, A. H. Quantum kinetic theory of current-induced torques in Rashba ferromagnets. Phys. Rev. B 86, 014416 (2012)

    Article  ADS  CAS  Google Scholar 

  35. Manchon, A., Matsumoto, R., Jaffres, H. & Grollier, J. Spin transfer torque with spin diffusion in magnetic tunnel junctions. Phys. Rev. B 86, 060404 (2012)

    Article  ADS  CAS  Google Scholar 

  36. Bass, J. & Pratt, W. P. Spin-diffusion lengths in metals and alloys, and spin-flipping at metal/metal interfaces: an experimentalist’s critical review. J. Phys. Condens. Matter 19, 183201 (2007)

    Article  ADS  CAS  Google Scholar 

  37. Tserkovnyak, Y., Brataas, A. & Bauer, G. E. W. Spin pumping and magnetization dynamics in metallic multilayers. Phys. Rev. B 66, 224403 (2002)

    Article  ADS  CAS  Google Scholar 

  38. Tserkovnyak, Y., Brataas, A., Bauer, G. E. W. & Halperin, B. I. Nonlocal magnetization dynamics in ferromagnetic heterostructures. Rev. Mod. Phys. 77, 1375–1421 (2005)

    Article  ADS  CAS  Google Scholar 

  39. Mosendz, O. et al. Detection and quantification of inverse spin Hall effect from spin pumping in permalloy/normal metal bilayers. Phys. Rev. B 82, 214403 (2010)

    Article  ADS  CAS  Google Scholar 

  40. Garate, I. & Franz, M. Inverse spin-galvanic effect in the interface between a topological insulator and a ferromagnet. Phys. Rev. Lett. 104, 146802 (2010)

    Article  ADS  CAS  Google Scholar 

  41. Yokoyama, T., Zang, J. & Nagaosa, N. Theoretical study of the dynamics of magnetization on the topological surface. Phys. Rev. B 81, 241410(R) (2011)

    Article  ADS  CAS  Google Scholar 

  42. Yokoyama, T. Current-induced magnetization reversal on the surface of a topological insulator. Phys. Rev. B 84, 113407 (2011)

    Article  ADS  CAS  Google Scholar 

  43. Tserkovnyak, Y. & Loss, D. Thin-film magnetization dynamics on the surface of a topological insulator. Phys. Rev. Lett. 108, 187201 (2012)

    Article  ADS  CAS  PubMed  Google Scholar 

  44. Mahfouzi, F., Nagaosa, N. & Nikolic, B. K. Spin-orbit coupling induced spin-transfer torque and current polarization in topological-insulator/ferromagnet vertical heterostructures. Phys. Rev. Lett. 109, 166602 (2012)

    Article  ADS  CAS  PubMed  Google Scholar 

Download references

Acknowledgements

We thank R. Buhrman, C.-F. Pai, N. Reynolds, J. Gibbons, A. Alemi and M. Bierbaum for discussions and assistance with experiments. Work at Cornell and Penn State was supported by DARPA (N66001-11-1-4110). We acknowledge additional funding for work at Cornell from the NSF/MRSEC-funded Cornell Center for Materials Research (DMR-1120296), the Army Research Office (W911NF-08-2-0032) and the NSF (DMR-1010768), and for work at Penn State from the Office of Naval Research (N00014-12-1-0117). A.R.M. acknowledges a DOE Office of Science graduate fellowship and J.L.G. acknowledges an NSF graduate fellowship. J.S.L. and N.S. acknowledge partial support through C-SPIN, one of six centres of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA. This work was performed in part at the Cornell NanoScale Facility and the Penn State Nanofabrication Facility, both nodes of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the NSF (ECS-0335765), and in the facilities of the Cornell Center for Materials Research.

Author information

Authors and Affiliations

  1. Cornell University, Ithaca, 14853, New York, USA

    A. R. Mellnik, J. L. Grab, P. J. Mintun, M. H. Fischer, A. Vaezi, E.-A. Kim & D. C. Ralph

  2. Department of Physics, The Pennsylvania State University, University Park, 16802, Pennsylvania, USA

    J. S. Lee, A. Richardella & N. Samarth

  3. Weizmann Institute of Science, Rehovot 76100, Israel,

    M. H. Fischer

  4. Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia,

    A. Manchon

  5. Kavli Institute at Cornell, Ithaca, 14853, New York, USA

    D. C. Ralph

Authors
  1. A. R. Mellnik
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. J. S. Lee
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. A. Richardella
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. J. L. Grab
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. P. J. Mintun
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. M. H. Fischer
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. A. Vaezi
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. A. Manchon
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. E.-A. Kim
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. N. Samarth
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. D. C. Ralph
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

A.R.M., J.S.L., A.R., N.S. and D.C.R. had the idea for and designed the experiments. A.R.M., J.L.G. and P.J.M. performed the sample fabrication, measurements and analysis. J.S.L., A.R. and N.S. developed the growth process for the Bi2Se3 layers. M.H.F., A.V., A.M. and E.-A.K. performed theoretical modelling. N.S. and D.C.R. provided oversight and advice. A.R.M. and D.C.R. wrote the manuscript and all authors contributed to its final version.

Corresponding author

Correspondence to D. C. Ralph.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Extended data figures and tables

Extended Data Figure 1 Change in resonant field as a function of direct current.

The data correspond to an 8 nm Bi2Se3/16 nm permalloy device with dimensions 50 μm × 15 μm, averaged over frequencies between 6 and 10 GHz. Error bars, 1 s.d.

Extended Data Figure 2 Measured linewidth versus frequency.

The data correspond to an 8 nm Bi2Se3/16 nm permalloy device with dimensions 50 μm × 10 μm at different direct currents. Error bars, 1 s.d.

Extended Data Figure 3 Control experiments.

a, A comparison between the ST-FMR signals measured for two 50 μm × 15 μm devices at 8 GHz, one with 8 nm Bi2Se3/16 nm permalloy and the other a single layer of 16 nm permalloy. The absorbed radio-frequency power was 5 dBm and ϕ = 45° in both cases. b, ST-FMR measurement for a 6 nm Pt/16 nm permalloy device with dimensions 80 μm × 24 μm. The absorbed power was 5 dBm and ϕ = 45°.

Extended Data Figure 4 Schematic band structures.

a, A schematic band structure with a Dirac surface state and a Rashba-split 2DEG as observed in refs 26, 32. b, The corresponding spin angular momentum structure at the Fermi energy.

Extended Data Figure 5 The predicted value of the out-of-plane spin torque ratio relative to the in-plane spin torque ratio.

as a function of , for = 5 nm.

Extended Data Figure 6 Anisotropic magnetoresistance calibration.

The data correspond to an 8 nm Bi2Se3/16 nm permalloy device with dimensions 50 μm × 15 μm, and were measured at room temperature.

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Mellnik, A., Lee, J., Richardella, A. et al. Spin-transfer torque generated by a topological insulator. Nature 511, 449–451 (2014). https://doi.org/10.1038/nature13534

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature13534

This article is cited by

Comments

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.

Search

Advanced search

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