Perturbation analysis of pairing symmetry and transition temperature in quasi-one-dimensional organic superconductors

We investigate pairing symmetry in quasi-one-dimensional organic supercondu ctors, solving Eliashberg's equation within third order perturbation theory for a repulsive Hubbard model. According to the calculation results, spin- singlet state is expected to give higher transition temperature than spin-t riplet one and the vertex corrections reduce the transition temperature for the spin-singlet case. It is shown that the contributions of antiferromagn etic spin fluctuations dominate strongly the momentum dependence of the eff ective pairing interaction for both of the spin-triplet and the spin-single t pairing cases.