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.
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References
Ashcroft, N. W. & Mermin, N. D. Solid State Physics Ch. 28, 561–587 (Saunders College, Fortworth, 1976)
Mott, N. Metal-Insulator Transitions Ch. 5, 145–169 (Taylar & Francis, London, 1990)
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)
Ekimov, E. A. et al. Superconductivity in diamond. Nature 428, 542–545 (2004)
Takano, Y. et al. Superconductivity in diamond thin films well above liquid helium temperature. Appl. Phys. Lett. 85, 2851–2853 (2004)
Baskaran, G. Resonating valence bond mechanism of impurity band superconductivity in diamond. Preprint at http://arXiv.org/cond-mat/0404286 (2004).
Boeri, L., Kortus, J. & Andersen, O. K. Three-dimensional MgB2-type superconductivity in hole-doped diamond. Phys. Rev. Lett. 93, 237002 (2004)
Lee, K.-W. & Pickett, W. E. Superconductivity in boron-doped diamond. Phys. Rev. Lett. 93, 237003 (2004)
Blasé, X., Adessi, Ch. & Connetable, D. Role of the dopant in the superconductivity of diamond. Phys. Rev. Lett. 93, 237004 (2004)
Nebel, C. E. & Ristein, J. Thin-film Diamond II Ch. 4–8, 121–358 (Elsevier, Amsterdam, 2004)
Zunger, A. & Freeman, A. J. Ground-state electronic properties of diamond in the local-density formalism. Phys. Rev. B 15, 5049–5065 (1977)
Collins, A. T. & Williams, A. W. S. The nature of the acceptor centre in semiconducting diamond. J. Phys. C 4, 1789–1800 (1971)
Kamakura, N. et al. Layer dependent band dispersion and correlation using soft X-ray ARPES. Europhys. Lett. 67, 240–246 (2004)
Inglesfield, J. E. & Plummer, E. W. in Angle-resolved Photoemission (ed. Kevan, S. D.) Ch. 2, 15–61 (Elsevier, Amsterdam, 1992)
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)
Matsushita, T. et al. Angle-resolved soft X-ray photoemission for the valence band of graphite. Surf. Rev. Lett. 9, 1321–1326 (2002)
Jimenez, I. et al. Accurate valence band width of diamond. Phys. Rev. B 56, 7215–7221 (1997)
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).
Campuzano, J. C., Norman, M. R. & Randeria, M. The Physics of Superconductors Vol. II, Ch. 5, 184 (Springer, Berlin/Heidelberg, 2004)
Umezawa, H. et al. Advantage on superconductivity of heavily boron-doped (111) diamond films. Preprint at http://arXiv.org/cond-mat/0503303 (2004).
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.
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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
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DOI: https://doi.org/10.1038/nature04278
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