The role of the dopant in the superconductivity of diamond

Abstract

We present an {\it ab initio} study of the recently discovered superconductivity of boron doped diamond within the framework of a phonon-mediated pairing mechanism. The role of the dopant, in substitutional position, is unconventional in that half of the coupling parameter $\lambda$ originates in strongly localized defect-related vibrational modes, yielding a very peaked Eliashberg ${\alpha }^{2}F(\omega )$ function. The electron-phonon coupling potential is found to be extremely large and T${}_C$ is limited by the low value of the density of states at the Fermi level.