The structure, energetics and magnetic properties of the quasi-hexagonal reconstruction of the Ir(100) surface and nanostructures formed by Fe atoms on this surface were investigated using first-principles density functional theory with generalized gradient corrections. It was found that the reconstructed (1 x 5) surface was 0.10eV/(1 x 1) area lower in energy than the unreconstructed surface and it was demonstrated that first-principles calculations could achieve quantitative agreement with experiment even for such long-period and deep-going reconstructions. For a Fe coverage of 0.4ML, a study was made of the stripe-like structure with bi-atomic Fe rows placed in the troughs of the (1 x 5)-reconstructed surface. Results of non-magnetic calculations agree well with the structure inferred from scanning tunnelling microscopy data. Higher Fe coverages lead to a de-reconstruction of the Ir substrate. At 0.8ML coverage a surface compound with composition Fe4Ir was formed, which showed an appreciable buckling. In this case, a ferromagnetic calculation led to good agreement with the low-temperature low-energy electron diffraction data. It was predicted that the (1 x 5) periodicity of the mixed interface layer would also persist in thicker films with a pure Fe surface. Films with 1 to 4ML of Fe were predicted to be tetragonally distorted and ferromagnetic, with an axial ratio corresponding well to an elastic distortion of the Fe lattice.

Reconstruction and De-Reconstruction of the Ir(100) Surface and UltraThin Fe/Ir(100) Films. D.Spišák, J.Hafner: Surface Science, 2003, 546[1], 27-38