Self-aligning atomic strings in surface-supported biomolecular gratings

We demonstrate the one-dimensional ordering of Co and Fe atoms employing supramolecular templates. Our low-temperature scanning tunneling microscopy observations reveal how individual adatoms spontaneously align with a preferred ~25 next-neighbor spacing in self-assembled methionine nanogratings on Ag(111). For Co strings the pertaining equilibrium statistics and dynamics were monitored to assess the underlying long-range interactions with their anisotropic energy landscape. The effect of the surface-state electron quantum confinement on the atomic self-alignment is revealed by tunneling spectroscopy mapping and ab initio calculations.