Structure and Electronic Properties of CoO Nanostructures on a Vicinal Pd(100) Surface

Abstract

Quasi-one-dimensional CoO nanostructures have been fabricated by step decoration growth on a Pd(1 1 23) surface, a vicinal of Pd(100). The step decoration is dominated by Co–Pd atomic exchange processes, which lead to the formation of 2–4 atom-row wide CoO nanostripes attached to and partially embedded into the outer terrace areas; the CoO stripes grow in a pseudomorphically strained hexagonal phase, as evidenced by atom-resolved scanning tunneling microscopy images and density functional theory simulations. A fraction of the Pd atoms ejected from the steps and outer terraces in the Co–Pd exchange assembles into short monatomic chains, which are periodically attached to the CoO steps. The local electronic structure of the CoO rows at the steps as measured by scanning tunneling spectroscopy is distinctly different from those of embedded CoO rows and of two-dimensional CoO monolayer phases at the terraces, with a significantly higher density of O 2p and Co 3d states around the Fermi energy as confirmed by d...