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:

Origin of the metallic properties of heavily boron-doped superconducting diamond

Abstract

The physical properties of lightly doped semiconductors are well described by electronic band-structure calculations and impurity energy levels1. Such properties form the basis of present-day semiconductor technology. If the doping concentration n exceeds a critical value nc, the system passes through an insulator-to-metal transition and exhibits metallic behaviour; this is widely accepted to occur as a consequence of the impurity levels merging to form energy bands2. However, the electronic structure of semiconductors doped beyond nc have not been explored in detail. Therefore, the recent observation of superconductivity emerging near the insulator-to-metal transition3 in heavily boron-doped diamond4,5 has stimulated a discussion on the fundamental origin of the metallic states responsible for the superconductivity. Two approaches have been adopted for describing this metallic state: the introduction of charge carriers into either the impurity bands6 or the intrinsic diamond bands7,8,9. Here we show experimentally that the doping-dependent occupied electronic structures are consistent with the diamond bands, indicating that holes in the diamond bands play an essential part in determining the metallic nature of the heavily boron-doped diamond superconductor. This supports the diamond band approach and related predictions, including the possibility of achieving dopant-induced superconductivity in silicon and germanium7. It should also provide a foundation for the possible development of diamond-based devices10.

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: Experimentally determined valence-band dispersions and the BZ of diamond.
Figure 2: Experimental band dispersions near E F as a function of boron concentration and the results of MDC analysis.

Similar content being viewed by others

References

  1. Ashcroft, N. W. & Mermin, N. D. Solid State Physics Ch. 28, 561–587 (Saunders College, Fortworth, 1976)

    Google Scholar 

  2. Mott, N. Metal-Insulator Transitions Ch. 5, 145–169 (Taylar & Francis, London, 1990)

    Book  Google Scholar 

  3. Bustarret, E., Gheeraert, F. & Watanabe, K. Dependence of the superconducting transition temperature on the doping level in single-crystalline diamond films. Phys. Rev. Lett. 93, 237005 (2004)

    Article  ADS  CAS  Google Scholar 

  4. Ekimov, E. A. et al. Superconductivity in diamond. Nature 428, 542–545 (2004)

    Article  ADS  CAS  Google Scholar 

  5. Takano, Y. et al. Superconductivity in diamond thin films well above liquid helium temperature. Appl. Phys. Lett. 85, 2851–2853 (2004)

    Article  ADS  CAS  Google Scholar 

  6. Baskaran, G. Resonating valence bond mechanism of impurity band superconductivity in diamond. Preprint at http://arXiv.org/cond-mat/0404286 (2004).

  7. Boeri, L., Kortus, J. & Andersen, O. K. Three-dimensional MgB2-type superconductivity in hole-doped diamond. Phys. Rev. Lett. 93, 237002 (2004)

    Article  ADS  Google Scholar 

  8. Lee, K.-W. & Pickett, W. E. Superconductivity in boron-doped diamond. Phys. Rev. Lett. 93, 237003 (2004)

    Article  ADS  Google Scholar 

  9. Blasé, X., Adessi, Ch. & Connetable, D. Role of the dopant in the superconductivity of diamond. Phys. Rev. Lett. 93, 237004 (2004)

    Article  ADS  Google Scholar 

  10. Nebel, C. E. & Ristein, J. Thin-film Diamond II Ch. 4–8, 121–358 (Elsevier, Amsterdam, 2004)

    Google Scholar 

  11. Zunger, A. & Freeman, A. J. Ground-state electronic properties of diamond in the local-density formalism. Phys. Rev. B 15, 5049–5065 (1977)

    Article  ADS  CAS  Google Scholar 

  12. Collins, A. T. & Williams, A. W. S. The nature of the acceptor centre in semiconducting diamond. J. Phys. C 4, 1789–1800 (1971)

    Article  ADS  CAS  Google Scholar 

  13. Kamakura, N. et al. Layer dependent band dispersion and correlation using soft X-ray ARPES. Europhys. Lett. 67, 240–246 (2004)

    Article  ADS  CAS  Google Scholar 

  14. Inglesfield, J. E. & Plummer, E. W. in Angle-resolved Photoemission (ed. Kevan, S. D.) Ch. 2, 15–61 (Elsevier, Amsterdam, 1992)

    Book  Google Scholar 

  15. Gravell, R. G. et al. X-ray photoemission cross-section modulation in Diamond, Silicon, Germanium, Methane, Silane, and Germane. Phys. Rev. B 7, 5313–5316 (1973)

    Article  ADS  Google Scholar 

  16. Matsushita, T. et al. Angle-resolved soft X-ray photoemission for the valence band of graphite. Surf. Rev. Lett. 9, 1321–1326 (2002)

    Article  ADS  CAS  Google Scholar 

  17. Jimenez, I. et al. Accurate valence band width of diamond. Phys. Rev. B 56, 7215–7221 (1997)

    Article  ADS  CAS  Google Scholar 

  18. Nakamura, J. et al. Holes in the valence band of superconducting boron-doped diamond film studied by soft X-ray absorption and emission spectroscopy. Preprint at http://arXiv.org/cond-mat/0410144 (2004).

  19. Campuzano, J. C., Norman, M. R. & Randeria, M. The Physics of Superconductors Vol. II, Ch. 5, 184 (Springer, Berlin/Heidelberg, 2004)

    Google Scholar 

  20. Umezawa, H. et al. Advantage on superconductivity of heavily boron-doped (111) diamond films. Preprint at http://arXiv.org/cond-mat/0503303 (2004).

Download references

Acknowledgements

We thank A. Chainani for valuable discussions and critical reading of the manuscript. We thank N. Yamada and J. Nakamura for discussions. We thank T. Kinoshita for supporting our experimental plan to do a doping dependence study. We thank I. Sakaguchi for SIMS measurements. This study was supported by Grants-in-Aid for Young Scientists and for Exploratory Research from Japan Society for the Promotion of Science.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to T. Yokoya.

Ethics declarations

Competing interests

Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Yokoya, T., Nakamura, T., Matsushita, T. et al. Origin of the metallic properties of heavily boron-doped superconducting diamond. Nature 438, 647–650 (2005). https://doi.org/10.1038/nature04278

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature04278

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

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