Stable and Metastable Structures of Cobalt on Cu(001): An ab initio Study

摘要

We report results of density-functional theory calculations on thestructural, magnetic, and electronic properties of (1x1)-structures of Co onCu(001) for coverages up to two monolayers. In particular we discuss thetendency towards phase separation in Co islands and the possibility ofsegregation of Cu on top of the Co-film. A sandwich structure consisting of abilayer Co-film covered by 1ML of Cu is found to be the lowest-energyconfiguration. We also discuss a bilayer c(2x2)-alloy which may form due tokinetic reasons, or be stabilized at strained surface regions. Furthermore, westudy the influence of magnetism on the various structures and, e.g., find thatCo adlayers induce a weak spin-density wave in the copper substrate.