Constraints on Tc for superconductivity in heavily boron-doped diamond

Calculations of electron-phonon coupling are performed for boron-doped diamond structures without electronically compensating defects over a wide range of boron concentration. The effects of boron substitutional disorder are incorporated through the use of randomly generated supercells, leading to a disorder-broadened distribution of results. After averaging over disorder, this study predicts a maximum bulk T(c) near 55 K for boron concentrations between 20% and 30%, assuming the validity of the simple structural model used and a Coulomb pseudopotential of mu*=0.12. Considering only the largest electron-phonon coupling values of the distribution, superconductivity may still percolate through the material at higher temperatures, up to 80 K, through the regions of large coupling. A synthesis path is proposed to experimentally access this class of materials.