Nature of Angle-Resolved Electron Energy Loss Spectrum

Abstract

Angle-resolved electron energy loss spectroscopy (AREELS) has been studied on the Si(111)7×7 surface by using a retarding field analyzer in a medium electron energy range (150≤E_p≤1000 eV) at the glancing incidence. Some fine structures are distinctly observed of surface and bulk state transitions as well as plasmon losses in the energy distribution curves N(E) at the specular Bragg reflection, but no transitions except for plasmon losses are observed at the back-ground position. AREELS spectra at the specular Bragg reflection are compared with those at the background position and with conventional angle-integrated electron energy loss spectra. AREELS spectra at the specular reflection are measured as a function of the primary energy around Bragg conditions.