High-Tc cuprates:: a new electronic state of matter?

The observation of high-temperature superconductivity in complex, layered cuprates by Bednorz and Muller must now rate as one of the greatest experimental discoveries of the last century. Identifying and understanding the microscopic origin of high-temperature superconductivity now stands as one of the greatest theoretical challenges as we enter this century. Although we are undeniably some way from a complete understanding of this remarkable natural phenomenon, we believe that evidence is accumulating for a new state of electronic matter, that of a charged Bose liquid of tightly bound pairs of small polarons, i.e., bipolarons. Thus, high-temperature superconductivity in the layered cuprates derives from the Bose-Einstein condensation (BEC) of bipolarons. (C) 2000 Elsevier Science B.V. All rights reserved.