A Possible Mechanism in the High-T_c Superconductivity Reflected on the Photoconductivity

Abstract

A series of experimental evidences has been recently established on “the Correlations of Novel Spectral Photoconductivity with Superconductivity” in the La₂–Cu₁–O_z, Y₁–Cu₂–O_z, and Y_3−x–Ba_x–Cu₃–O_9−y systems, which clearly feature the excitons and polarons in the Cu₂O-like part in these systems with various degrees of oxygen deficiency. On the basis of these results as the silhouette induced by photoexcitation, we propose here a possibility of the realistic mechanism of the formations of pairs and eventually of “a coherent ensemble of united polarons and excitons” in the ground state of the high-T_c superconductivity. We condense our idea into a term of “the exciton-mediated bipolarons”.