We investigate the origin of superconductivity in boron-doped silicon carbide using a first-principles approach. The strength of the electron-phonon coupling calculated for cubic SiC at the experimental doping level suggests that the superconductivity observed in this material is phonon mediated. Analysis of the $2H\text{-SiC}$, $4H\text{-SiC}$, $6H\text{-SiC}$, and $3C\text{-SiC}$ polytypes indicates that superconductivity depends on the stacking of the Si and C layers and that the cubic polytype will exhibit the highest transition temperature. In contrast to the cases of silicon and diamond, acoustic phonons are found to play a major role in the superconductivity of silicon carbide.

• Received 29 September 2008

DOI:https://doi.org/10.1103/PhysRevB.79.104511