Structural and electronic properties of the Au(001)/Fe(001) interface from density functional theory calculations

A density functional theory (DFT) investigation of the structural and electronic properties of the Au(001)/Fe(001) interface, as a function of the number of Au layers deposited on the Fe substrate (from 1 to 11 Au monolayers), is presented. The elastic effects on the interface properties due to the lattice mismatch between Fe and Au, calculated by DFT using the generalized gradient approximation, are also evaluated. At the interface, the interlayer distances in the Fe substrate as well as in the Au slab expand. The Fe atoms of the interface exhibit an enhanced magnetic moment and the Au atoms of the interface bear a nonzero (but very low) magnetic moment. The calculated interface energy favors the formation of core-shell Fe@Au nanoparticles, where Au(001) is in epitaxy at 45 degrees on (001) facets of a Fe nanocube. Finally, the analysis of the electronic properties shows that the work of adhesion of the interface is maximum for a coating of Fe with 2 Au monolayers, which can be explained by a strong overlap between the electronic densities of the Fe interface atoms with those of the Au surface atoms.