Electron-phonon superconductivity in noncentrosymmetric LaNiC2: First-principles calculations

We report first-principles calculations of the electronic structure and electron-phonon coupling in the noncentrosymmetric superconductor LaNiC2. These show that the material is a conventional electron-phonon superconductor with intermediate coupling. There are large contributions to the coupling by two low-frequency C nonbond-stretching modes, one of which has strong Kohn anomalies. Since LaNiC2 lacks inversion symmetry, the pairing is of dominant s -wave type with some mixture of p -wave character. This will give exponential decay in the specific heat.