ANGLE-RESOLVED-PHOTOEMISSION STUDY OF THE BAPB0.81BI0.19O3 (001) SURFACE

Synchrotron-excited angle-resolved photoemission data for a cleaved single-crystal ${\mathrm{BaPb}}_{0.81}$${\mathrm{Bi}}_{0.19}$${\mathrm{O}}_{3}$ (001) surface are presented. Enhancements in spectral intensity at the Fermi energy away from the \ensuremath{\Gamma} point are shown to be in reasonable agreement with linear-augmented-plane-wave band-structure calculations [Phys. Rev. B 28, 4227 (1983)]. The rapid surface degradation of metallic and superconducting compositions in the ${\mathrm{BaPb}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Bi}}_{\mathit{x}}$${\mathrm{O}}_{3}$ system is discussed.