High-resolution angle-resolved photoemission study of the Fermi surface and the normal-state electronic structure of Bi₂Sr₂CaCu₂O₈

High-resolution angle-resolved photoelectron spectroscopic measurements were made of the Fermi edge of a single crystal of Bi₂Sr₂CaCu₂O₈ at 90 K along several directions in the Brillouin zone. The resultant Fermi-level crossings are consistent with local-density band calculations, including a point calculated to be of Bi-O character. Additional measurements were made where bands crossed the Fermi level between 100 and 250 K, along with measurements on an adjacent Pt foil. The Fermi edges of both materials agree to within the noise. Below the Fermi level the spectra show correlation effects in the form of an increased effective mass, but the essence of the single-particle band structure is retained. The shape of the spectra can be explained by a lifetime-broadened photohole and secondary electrons. The effective inverse photohole lifetime is linear in energy.