Superconductivity in boron-doped diamond

Superconductivity of boron-doped diamond, reported recently at T-c=4 K, is investigated exploiting its electronic and vibrational analogies to MgB2. The deformation potential of the hole states arising from the C-C bond-stretch mode is 60% larger than the corresponding quantity in MgB2 that drives its high T-c, leading to very large electron-phonon matrix elements. The calculated coupling strength lambdaapproximate to0.5 leads to T-c in the 5-10 K range and makes phonon coupling the likely mechanism. Higher doping should increase T-c somewhat, but the effects of three dimensionality primarily on the density of states keep doped diamond from having a T-c closer to that of MgB2.