Photoemission study of the new high-temperature superconductor Bi-Ca-Sr-Cu-O

Abstract

We present the first photoemission data on the recently discovered family of high-temperature superconductors that do not include rare earths. Synchrotron-radiation photoemission spectra were taken both on sintered and on cleaved single-crystal specimens of ${\mathrm{Bi}}_4{\mathrm{Ca}}_3{\mathrm{Sr}}_3{\mathrm{Cu}}_4{\mathrm{O}}_{16+x}$. Both samples were single phase and had sharp superconducting transitions at 85 K. The differences and similarities with respect to $\mathrm{Y}{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-x}$ are discussed, and the data are compared to the results of one-electron density-of-states calculations.