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 $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}x}$ are discussed, and the data are compared to the results of one-electron density-of-states calculations.