PAIRING STATE OF HIGH-T-C SUPERCONDUCTORS - COMMENTS ON THE JOSEPHSON EFFECT EXPERIMENTS IN THE CONTEXT OF THE S-WAVE VS D-WAVE DEBATE

A variety of experimental investigations has been developed in the last years toward the identification of the symmetry of the order parameter in high-T-c superconductors. A short review of the main experiments employing the Josephson effect as a probe for the determination of the symmetry of the pairing state is given. Conflicting data are discussed which evidence the coexistence of certainties and ambiguities.