Transition metal superlattices and epitaxial films on Ir(100)-(5×1)-H

The nanostructured phase Ir(100)-(5×1)-H is used as a template for the self-organized formation of nanometer-scaled lateral superlattices of the transition metals (TMs) Fe, Co, and Ni. Initially, Fe atoms decorate the monatomic Ir wires which reside in fivefold periodicity on the template. This is in contrast to Co and Ni which form islands within the adsorption stripes between and across the Ir wires. In no case there is intermixing with substrate atoms. At 0.8 monolayer coverage all stripe sites are filled so that lateral {TM₄Ir} superlattices are formed. With further deposition a second TM layer grows, whereby the Ir wires at the interface remain immobile. Due to the different radii of atoms within the interface layer a substantial buckling is imprinted in the growing film as well as in the supporting substrate. The related morphology and crystallographic structure of the films are determined by atomically resolved scanning tunneling microscopy and quantitative low-energy electron diffraction.