Sub-Terahertz spectroscopy of superconducting diamond

In this framework, it has been discovered that boron-doped diamond can also become a superconductor below critical temperatures Tc well above the liquid helium temperature. The strongly covalent bonds, the high concentration of impurities, and the high energy of its optical phonon in comparison with the Fermi energy, make diamond much different from the conventional metals where the BCS theory of superconductivity holds. Here the reflectivity of superconducting diamond is measured down to sub-terahertz frequencies. Our results consistently indicate that diamond, in spite of the above cited peculiarities, behaves as a BCS superconductor in the "dirty" regime.