Kinetic pathway for the formation of Fe nanowires on stepped Cu(111) surfaces

We report the discovery of a novel kinetic pathway for the formation of one-dimensional Fe nanowires of single atom width on stepped Cu(111) surfaces. This pathway, identified through extensive total-energy calculations within density functional theory, establishes that the stable structure involves a row of Fe atoms on the upper edge of a step. The formation of the surface wire is preceded by facile incorporation of an initial row of Fe atoms into the surface layer at one lateral lattice constant away from the step edge, which then acts as an attractor for the second exposed row of atoms. The resulting wire structure provides a natural interpretation of existing experimental results. We also explore the applicability of this mechanism in the formation of other related systems.