Cu(111) Electron Band Structure and Channeling by VLEED

Abstract

Very-low-energy electron diffraction (VLEED) intensities from clean Cu(111) surface have been measured in detail in the energy range 15 to 35 eV by low-energy electron microscope. Corresponding theoretical I-V curves are obtained in good agreement with experimental data when the anisotropy of the electron attenuation is taken into account. The coincidence of the peaks in the I-V curves at normal incidence with two kinds of energy gaps of the electron band structure of the copper crystal (Ek d =0) is interpreted. The small width of the resonance peak in the I-V curve at normal incidence is explained in terms of electron surface channeling. VLEED thus provides information about the unoccupied part of the electron band structure of copper which complements that obtained from angular resolved photoemission.