Angle-resolved photoemission studies of single-crystal YBa2Cu3O7−x

Abstract

We present the first angle-resolved photoemission and low-energy electron-diffraction (LEED) results obtained from clean single-crystal ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{7\mathrm{-}\mathrm{x}}$ (001) surfaces prepared by cleaving in a vacuum. The surfaces exhibit (1×1)-ordered LEED patterns, but many of the photoemission features exhibit little or no angular dependence. The most important exception is the upper spectral edge, which shows angular dispersion and a strong photon energy dependence.