Quantum wire behavior in a one-component metallic system: monatomic Cu chains on Cu(1 1 1)

Low-temperature scanning tunneling microscopy was used to assemble monatomic Cu chains on Cu(1 1 1) by atomic manipulation at View the MathML source and to explore their electronic structure. Tunneling spectroscopy reveals the formation of unoccupied chain-localized states in the pseudogap of the projected Cu bulk bandstructure. The dispersion of these states is fully described by tight binding behavior. Density functional theory calculations confirm the formation of unoccupied states in the relevant energy regime and in addition predict the existence of occupied states trapped in the pseudogap.