KEY FEATURES IN THE MEASURED BAND-STRUCTURE OF BI2SR2CACU2O8- FLAT BANDS AT E(F) AND FERMI-SURFACE NESTING(DELTA )

The near-E(F) electronic structure and Fermi surface of Bi2Sr2CaCu2O8delta have been mapped out with angle-resolved photoemission. Key feat ures of the measured band structure are (1) an extended region of flat CuO2 derived bands very near E(F) and (2) a strong propensity for Fer mi surface nesting. Comparative analysis of these data with those from other cuprate superconductors suggests that these features may be res ponsible for many of the anomalous physical properties of the p-type c uprates, while the absence of these features may be related to the mor e ''normal'' physical properties of the n types.