Quantum interference and long-range adsorbate-adsorbate interactions

Density functional theory and scanning tunneling microscopy are used to resolve the long-range adsorbate interactions between Co adatoms on Cu~111!, caused by the quantum interference of surface-state electrons. Our calculations and experimental results are in very good quantitative agreement. We reveal the effect of the quantum interference of surface state electrons on adatom motion, leading to the self-assembly of onedimensional structures on metal surfaces.