Superconductivity in diamond

Abstract

We survey methods of synthesis of boron doped diamond with high pressure-high temperature techniques. New route is proposed for synthesis of relatively large heavily boron doped diamond single crystals, which exhibit superconductivity. Superconducting boron-doped diamond samples were synthesized with isotopes of 10B, 11B, 13C and 12C. We claim the presence of a carbon isotope effect on the superconducting transition temperature, which supports the “diamond–carbon”-related nature of superconductivity and the importance of the electron–phonon interaction as the mechanism of superconductivity in diamond. Isotope substitution permits us to relate almost all bands in the Raman spectra of heavily boron-doped diamond to the vibrations of carbon atoms. The 500 cm − 1 Raman band shifts with either carbon or boron isotope substitution and may be associated with vibrations of paired or clustered boron.