The role of the dopant in the superconductivity of diamond

TL;DR

This study uses ab initio methods to analyze how boron dopants induce superconductivity in diamond, highlighting the importance of localized vibrational modes and electron-phonon interactions.

Contribution

It reveals the unconventional role of boron dopants, showing that localized vibrational modes significantly contribute to the pairing mechanism in doped diamond.

Findings

Half of the electron-phonon coupling comes from defect-related vibrational modes.

The electron-phonon coupling potential is extremely large.

The critical temperature is limited by the low density of states at the Fermi level.

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 $\alpha^2F(\omega)$ 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.