Model for the boron-doping dependence of the critical temperature of superconducting boron-doped diamond

Abstract

We study the concentration dependence of the superconducting critical temperature Tc in a boron-doped diamond. We evaluate the density of states at Fermi level N0 within the dynamical cluster approximation obtaining higher values than from the coherent potential approximation. We discuss Tc as a function of N0 within the BCS, the McMillan and the Belitz theory. The simplified Belitz theory gives the best agreement with experimental data. Since the density of states follows a simple power law for accessible doping concentrations x, the present theory offers an analytical formula for Tc(x). © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.