Charge fluctuation induced superconductivity in α-(ET)2I3 salt

We examine order parameter of superconducting (SC) state in quasi-two-dimensional organic conductor, alpha-(ET)(2)I-3 salt under uniaxial pressure. The SC state has been found at temperature below the charge ordering temperature. The SC state is enhanced in the vicinity of the boundary between the metal and the narrow gap semiconductor due to the interplay of many bands and repulsive interactions. Such a scenario has been demonstrated in terms of a linearized gap equation. By calculating pairing interaction in terms of RPA, it is shown that the order parameter for the SC state is extremely anisotropic extended-S symmetry. (c) 2005 Published by Elsevier B.V.