Study of the N–Cu(100) system

Abstract

The reaction of a clean Cu(100) surface with atomic N has been studied with low energy electron diffraction (LEED), Auger electron spectroscopy, ultraviolet photoemission spectroscopy (UPS), and x-ray photoemission spectroscopy (XPS). Atomic nitrogen, formed by electron dissociation of N2 forms a c(2×2) overlayer on the Cu(100) surface. An analysis of LEED intensity profiles averaged over constant momentum transfer indicates that the N binds in a fourfold symmetric site, 0.145 nm above the first layer of Cu atoms. UPS data reveal small adsorbate-induced electronic levels at 1.3 and 5.8 eV below the Fermi level, in addition to rather complex changes in the Cu d band. XPS measurements yield 397.3 eV for the binding energy of the N 1s electrons with respect to the Fermi level. Our UPS and Auger data on Cu(100)/N in terms of N-induced states is shown to be plausible.