Geometrie and electronic structure of passive CuN monolayer on Cu(111): A scanning tunneling microscopy and spectroscopy study

An insulating CuN monolayer was grown on a Cu(111) surface; subsequently, the dynamic growth process, the reconstructed geometric structure and the electronic structure were studied using scanning tunneling microscopy. Confirmation of the atomic model of the pseudo-(100) layer, proposed by Higgs et al. and Driver et al. was made. In addition, we observed a small misalignment of the super cell away from the <110> direction of the Cu substrate, resulting in long range distortion. A large insulator-like band gap of ∼ 3.3 eV was measured through the CuN surface. The CuN monolayer can be used as a model surface on which the electronic structure of an atom or a molecule is explored by scanning tunneling microscopy. This electronic structure can not be perturbed by the metallic substrate, despite the tunneling of electrons through the surface layer.