Abstract
The exploration of topological Dirac semimetals with intrinsic superconductivity can be a most plausible way to discover topological superconductors. We propose that type-II Dirac semimetal states exist in the band structure of TaC, a well-known s-wave superconductor, by using the first-principles calculations and the k ⋅ p effective model. The tilted gapless Dirac cones, which are composed of Ta d and C p orbitals and are protected by C4v symmetry, are found to be below the Fermi level. The bands from Ta d orbitals are greatly coupled with the acoustic modes around the zone boundary, indicating their significant contribution to the superconductivity. The relatively high transition temperature ∼10.5 K is estimated to be consistent with the experimental data. To bring the type-II Dirac points close to chemical potential, hole doping is needed. This seems to decrease the transition temperature a lot, making the realization of topological superconductivity impossible.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have