Saturation of the Image Potential Observed in Low-Energy Electron Reflection at Cu(001) Surface

Abstract

High-resolution low-energy electron-diffraction measurements of the (00) beam from Cu(001) are reported. Fine structure near the (11) beam threshold is explained by an interference between the directly reflected wave and a wave internally reflected at the surface potential barrier. With use of this interpretation, the observed lineshapes have been fitted by adjusting two parameters describing the shape of the potential. It is concluded that the long-range potential saturates to a value about one-half the crystal inner potential.