ELECTRONIC-STRUCTURE EVOLUTION FROM MOTT INSULATOR TO SUPERCONDUCTOR - AN ANGLE-RESOLVED PHOTOEMISSION INVESTIGATION

A critical analysis of new and earlier experimental data from the cupr ate superconductors, in light of recent advances in many-body theory, shows that effects previously thought to be explained by band theory a lone (such as the large Fermi surface) may also be accounted for by an idealized many-body approach. In addition, there are many elements of the data which can be better described using many-body approaches. Th erefore, it appears that a comprehensive many-body description is need ed to understand the electronic structure of the cuprate superconducto rs in the normal state. Angle-resolved photoemission has also revealed a large gap anisotropy, fueling the current debate on the symmetry of the pairing state.