Superconductivity in nitrogen-doped 3C-SiC from first-principles calculations

The electronic structure and the lattice dynamics of N-doped 3C-SiC have been studied using the first-principles calculations. Electrons are introduced to the conduction band bottom at the X-point of the Brillouin zone. It is revealed that the acoustical modes and optical modes soften upon N doping. The softened acoustical modes contribute over twice of what the optical modes do to the electron-phonon coupling strength. We predict that the superconductivity will occur with N doping concentration beyond about 3 at.% and the transition temperature can reach 11.36 K upon doping of N at about 5 at.% for 3C-SiC.