ATOMIC AND MAGNETIC-STRUCTURE OF FCC FE/CU(100)

The atomic and magnetic structure of fcc Fe grown on Cu(100) are determined using spin-density-functional theory and the full-potential linear muffin-tin orbital method. Different types of interlayer and intralayer magnetism are investigated. For films of four up to eleven adsorbed Fe layers our ab initio total-energy calculations always give a ferromagnetic intralayer spin ordering of the Fe atoms. The surface and first subsurface layers couple ferromagnetically, whereas the deeper ones show interlayer antiferromagnetic coupling. This magnetic ordering is accompanied by a 3.9% expansion of the first layer spacing and a 1% contraction of the second, which agree well with low-energy electron diffraction analyses. We link the results to ground-state calculations for fcc iron.