Superconductivity and magnetism in non-centrosymmetric system: Application to CePtSi

Superconductivity and magnetism in the non-centrosymmetric heavy fermion compound CePtSi and related materials are theoretically investigated. On the basis of the random phase approximation (RPA) analysis of the extended Hubbard model, we describe the helical spin fluctuation induced by the Rashba-type anti-symmetric spin-orbit coupling and identify two stable superconducting phases with either the dominant p-wave (s+P-wave) symmetry or the d-wave (p+D+f-wave) symmetry. The effect of the coexistent antiferromagnetic order is investigated in both states. The superconducting order parameter, quasiparticle density of state, NMR 1=TT, specific heat, anisotropy of H, and possible multiple phase transitions are discussed in detail. A comparison with experimental results indicates that the s+P-wave superconducting state is likely realized in CePtSi. ©2008 The Physical Society of Japan.