Complex reconstruction ofγ-iron multilayers on Cu(100):Ab initiolocal-spin-density investigations

First-principles local-spin-density investigations of complex reconstructions of thin $\gamma$-iron films epitaxially grown on Cu(100) surfaces are presented. It is shown that quite substantial lateral and vertical modulations of the surface (and partly also of the deeper layers) can occur. The reconstructions are most pronounced at a thickness where the transition occurs from the ferromagnetic regime observed in the thinnest films to the antiferromagnetic bilayer configurations characteristic for the thicker films. The theory agrees quite well with experimental results for thermally deposited films (although some characteristic differences exist).