Photoemission electronic states of thallium- and bismuth-based superconductors

X-ray photoemission spectra the core-levels as well as the X-ray photoemiss ion spectra and ultraviolet photoemission spectra from the Valence bands of the (Tl0.6Pb0.5)(ST0.9 Ba-0.1)Ca2Cu3Oy and (Bi1.75Pb0.35)Sr1.9Ca2.05CU3.05 Oy superconductors were measured and analyzed. Special attention was paid t o the valence band X-ray photoemission spectra and ultraviolet photoemissio n spectra, the Cu 2p core-level X-ray photoemission spectra and the Cu L-2, L-3-M4,5M4,5 and O K-L2,3L2,3 Auger spectra. Both Cu 2p(3/2) and Cu 2p(1/2) core-level lines consisted of two spin-orbit split main lines accompanied with the two satellite lines. The charge transfer energy Delta from the oxy gen ligand to the copper 3d(9) states and the hopping integral t were estim ated from the energy separation between the main line and the satellite lin e taking advantage of the local cluster model calculations and their extens ion to high-temperature superconductors. The Coulomb correlation on-site en ergy U-dd of two electrons in the same copper orbital and U-pp Of two elect rons in the oxygen orbital as well as the correlation energy U-cd of the 2p core hole - 3d electron interaction have been estimated from the Auger ele ctron spectra and the valence band spectra. They are: U-dd = 6.0 +/- 0.5 eV , of U-pp congruent to 10 +/- 1 eV and of U-cd congruent to 8.0 +/- 0.5 eV nearly the same for both the Tl- and Bi-compounds. We conclude that these c ompounds are the charge transfer strongly-correlated metals.