Fermi surface and superconducting properties of non-centrosymmetric LaNiC ₂

We succeeded in growing single crystals of LaNiC ₂ with the non-centrosymmetric orthorhombic structure by the Czochralski method, and measured the electrical resistivity, de Haas-van Alphen effect, and specific heat to clarify the Fermi surface and superconducting properties. This compound has been studied from a viewpoint of the triplet superconducting pairing state. In the present experiment, we observed an ellipsoidal Fermi surface and a multiply-connected-pillar Fermi surface, which are split into two Fermi surfaces, reflecting the antisymmetric spin-orbit interaction based on the non-centrosymmetric crystal structure. The two ellipsoidal Fermi surfaces are split by 230 K, for example. The anisotropy of electrical resistivity and upper critical field H _c2 in superconductivity are not large for three principal directions. From the low-temperature specific heat measurement, superconductivity in LaNiC ₂ is explained by the framework of the BCS-superconductivity, contrary to the above arguments. The upper critical field H _c2(0), which was obtained from the specific heat under magnetic fields, is about 2kOe.