Structural and Chemical Properties of Gold Rare Earth Disilicide Core?Shell Nanowires

摘要

Clear understanding of the relationship between electronic structure and chemical activity will aid in the rational design of nanocatalysts. Core?shell Au-coated dysprosium and yttrium disilicide nanowires provide a model atomic scale system to understand how charges that transfer across interfaces affect other electronic properties and in turn surface activities toward adsorbates. Scanning tunneling microscopy data demonstrate self-organized growth of Au-coated DySi_2 nanowires with a nanometer feature size on Si(001), and Kelvin probe force microscopy data measure a reduction of work function that is explained in terms of charge transfer. Density functional theory calculations predict the preferential adsorption site and segregation path of Au adatoms on Si(001) and YSi_2. The chemical properties of Au?YSi_2 nanowires are then discussed in light of charge density, density of states, and adsorption energy of CO molecules.