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:

Dirac electron states formed at the heterointerface between a topological insulator and a conventional semiconductor

Abstract

Topological insulators are a class of semiconductor exhibiting charge-gapped insulating behaviour in the bulk, but hosting a spin-polarized massless Dirac electron state at the surface1,2,3,4. The presence of a topologically protected helical edge channel has been verified for the vacuum-facing surface of several topological insulators by means of angle-resolved photoemission spectroscopy5,6,7 and scanning tunnelling microscopy8,9,10. By performing tunnelling spectroscopy on heterojunction devices composed of p-type topological insulator (Bi1xSbx)2Te3 and n-type conventional semiconductor InP, we report the observation of such states at the solid-state interface. Under an applied magnetic field, we observe a resonance in the tunnelling conductance through the heterojunction due to the formation of Landau levels of two-dimensional Dirac electrons at the interface. Moreover, resonant tunnelling spectroscopy reveals a systematic dependence of the Fermi velocity and Dirac point energy on the composition x. The successful formation of robust non-trivial edge channels at a solid-state interface is an essential step towards functional junctions based on topological insulators11,12,13.

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

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

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

Figure 1: Tunnelling spectroscopy in a topological insulator/non-topological insulator p–n junction.
Figure 2: Landau-level formation observed in tunnelling spectra.
Figure 3: Angular dependence of Landau-level formation.
Figure 4: Composition dependence of Fermi velocity and energy of Dirac point in (Bi1xSbx)2Te3.

Similar content being viewed by others

References

  1. Kane, C. L. & Mele, E. J. Z2 topological order and the quantum spin Hall effect. Phys. Rev. Lett. 95, 146802 (2005).

    Article  CAS  Google Scholar 

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

    Article  Google Scholar 

  3. Moore, J. E. & Balents, L. Topological invariants of time-reversal-invariant band structures. Phys. Rev. B 75, 121306(R) (2007).

    Article  Google Scholar 

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

    Article  CAS  Google Scholar 

  5. Hsieh, D. et al. A topological Dirac insulator in a quantum spin Hall phase. Nature 452, 970–974 (2008).

    Article  CAS  Google Scholar 

  6. Chen, Y. L. et al. Experimental realization of a three-dimensional topological insulator, Bi2Te3 . Science 325, 178–181 (2009).

    Article  CAS  Google Scholar 

  7. Hsieh, D. et al. A tunable topological insulator in the spin helical Dirac transport regime. Nature 460, 1101–1105 (2009).

    Article  CAS  Google Scholar 

  8. Cheng, P. et al. Landau quantization of topological surface states in Bi2Se3 . Phys. Rev. Lett. 105, 076801 (2010).

    Article  Google Scholar 

  9. Hanaguri, T., Igarashi, K., Kawamura, M., Takagi, H. & Sasagawa, T. Momentum-resolved Landau-level spectroscopy of Dirac surface state in Bi2Se3 . Phys. Rev. B 82, 081305(R) (2010).

    Article  Google Scholar 

  10. Jiang, Y. et al. Landau quantization and the thickness limit of topological insulator thin films of Sb2Te3 . Phys. Rev. Lett. 108, 016401 (2012).

    Article  Google Scholar 

  11. Fu, L. & Kane, C. L. Superconducting proximity effect and Majorana fermions at the surface of a topological insulator. Phys. Rev. Lett. 100, 096407 (2008).

    Article  Google Scholar 

  12. Qi, X. L., Hughes, T. L. & Zhang, S. C. Topological field theory of time-reversal invariant insulators. Phys. Rev. B 78, 195424 (2008).

    Article  Google Scholar 

  13. Seradjeh, B., Moore, J. E. & Franz, M. Exciton condensation and charge fractionalization in a topological insulator film. Phys. Rev. Lett. 103, 066402 (2009).

    Article  CAS  Google Scholar 

  14. Klein, J., Leger, A., Belin, M., Defourneau, D. & Sangster, M. J. L. Inelastic-electron-tunneling spectroscopy of metal–insulator–metal junctions. Phys. Rev. B 7, 2336–2348 (1973).

    Article  CAS  Google Scholar 

  15. Bockenhoff, E., Klitzing, K. V. & Ploog, K. Tunneling from accumulation layers in high magnetic fields. Phys. Rev. B 38, 10120–10123 (1988).

    Article  CAS  Google Scholar 

  16. Yang, C. H., Yang, M. J. & Kao, Y. C. Magnetotunneling spectroscopy in a double-barrier heterostructure: Observation of incoherent resonant-tunneling processes. Phys. Rev. B 40, 6272–6276 (1989).

    Article  CAS  Google Scholar 

  17. Zhang, J. et al. Band structure engineering in (Bi1−xSbx)2Te3 ternary topological insulators. Nature Commun. 2, 574 (2011).

    Article  Google Scholar 

  18. Qu, D. X., Hor, Y. S., Xiong, J., Cava, R. J. & Ong, N. P. Quantum oscillations and Hall anomaly of surface states in the topological insulator Bi2Te3 . Science 329, 821 (2010).

    Article  CAS  Google Scholar 

  19. Analytis, J. G. et al. Two-dimensional surface state in the quantum limit of a topological insulator. Nature Phys. 6, 960–964 (2010).

    Article  CAS  Google Scholar 

  20. Taskin, A. A., Ren, Z., Sasaki, S., Segawa, K. & Ando, Y. Observation of Dirac holes and electrons in a topological insulator. Phys. Rev. Lett. 107, 016801 (2011).

    Article  CAS  Google Scholar 

  21. Sacepe, B. et al. Gate-tuned normal and superconducting transport at the surface of a topological insulator. Nature Commun. 2, 575 (2011).

    Article  Google Scholar 

  22. Levinstein, M., Rumyantsev, S. & Shur, M. Handbook Series on Semiconductor Parameters (World Scientific, (1996).

    Book  Google Scholar 

  23. Hao, G. et al. Synthesis and characterization of few-layer Sb2Te3 nanoplates with electrostatic properties. RSC Advances 2, 10694–10699 (2012).

    Article  CAS  Google Scholar 

  24. Esaki, L. New phenomenon in narrow germanium p–n junctions. Phys. Rev. 109, 603–604 (1958).

    Article  CAS  Google Scholar 

  25. Winkler, R. Spin–Orbit Coupling Effects in Two-Dimensional Electron and Hole Systems (Springer, (2003).

    Book  Google Scholar 

  26. Xiong, J. et al. High-field Shubnikov–de Haas oscillations in the topological insulator Bi2Te2Se. Phys. Rev. B 86, 045314 (2012).

    Article  Google Scholar 

  27. Chen, J. et al. Gate-voltage control of chemical potential and weak antilocalization in Bi2Se3 . Phys. Rev. Lett. 105, 176602 (2010).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This research was supported by the Japan Society for the Promotion of Science through the Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program) on ‘Quantum Science on Strong Correlation’ initiated by the Council for Science and Technology Policy and by JSPS Grant-in-Aid for Scientific Research(S) No. 24224009 and No. 24226002.

Author information

Authors and Affiliations

Authors

Contributions

Y.T. conceived the project. R.Y. and K.K. grew the thin films, made the devices and performed the tunnelling spectroscopy measurements. R.Y. analysed the data and wrote the manuscript with contributions from all authors. A.T., J.G.C., K.S.T., M.K. and Y.T. jointly discussed the results.

Corresponding author

Correspondence to R. Yoshimi.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 1105 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Yoshimi, R., Tsukazaki, A., Kikutake, K. et al. Dirac electron states formed at the heterointerface between a topological insulator and a conventional semiconductor. Nature Mater 13, 253–257 (2014). https://doi.org/10.1038/nmat3885

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nmat3885

This article is cited by

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