Structural and magnetic properties of ultrathin fcc Fe films on Cu(001): Full-potential LAPW studies - art. no. 115417

Full-potential linearized-augmented-plane-wave calculations using both loca l-spin-density (LSDA) and generalized gradient Perdew-Burke-Ernzerhof (PBE) functionals are performed to investigate structural and magnetic propertie s of Cu(001)-Fe film systems with up to three Fe layers. In the calculation s full interlayer distance optimizations of the surface systems are carried out allowing both Fe and Cu surface layers to relax. The LSDA calculations yield Fe-Fe and Fe-Cu interlayer spacings which are always smaller compare d to Cu bulk, while the PBE results show expanded interlayer distances in a greement with experiment. The supported Fe films are found to be ferromagne tic in the ground state, where the layer-resolved magnetic moments are incr eased with respect to bulk Fe values. The increase is always largest for th e topmost layer and becomes smaller for the sublayers, which is consistent with previous theoretical studies on unrelaxed Cu(001)-Fe systems. In addit ion, geometry optimizations of Cu(001)-Fe with different spin orientation b etween the Fe layers show chat parallel spin directions of neighboring laye rs lead to an expanded interlayer distance, whereas antiparallel spin resul ts in contracted interlayer spacing. The geometric effect of interlayer rel axation is found to be significant for the Cu(001)-Fe systems, while magnet ic properties of the Fe overlayers are affected less by relaxation.