kappa-BEDT-TTF salts as layered correlated electron systems

The kappa-ET(2)X compounds are classified as strongly correlated electron systems. The tight-binding approach for correlated electrons is presented. The anisotropic superconducting pairing interaction is constructed based on the symmetry of electronic transfer integral and superconducting characteristics are calculated. For superconducting and normal properties, a decisive role of internal degrees of freedom in ET-layers, particularly in the ET(2) dimers is shown. The nodes of superconducting order parameter are reasonable for description of low energy experiments: nonactivated temperature dependence of superconducting specific heat and NMR relaxation rate.