Systematic ab initio study of the electronic and magnetic properties of different pure and mixed iron systems

We present a theoretical study of the electronic and magnetic properties of iron systems in different environments: pure iron systems [dimer, bcc bulk , (100) surface, and free-standing iron monolayer], and low-dimensional iro n systems deposited on Ag (100) surface (monoatomic linear wires, iron mono layer, planar, and three-dimensional clusters). Electronic and magnetic pro perties have been calculated using a recently developed total-energy first- principles method based on density-functional theory with numerical atomic orbitals as a basis set for the description of valence electrons and nonloc al pseudopotentials for the atomic core. The Kohn-Sham equations are solved self-consistently within the generalized gradient approximation for the ex change-correlation potential. Tests on the pseudopotential, the basis set, grid spacing, and k sampling an carefully performed. This technique, which has been proved to be very efficient for large nonmagnetic systems, is appl ied in this paper to calculate electronic and magnetic properties of differ ent iron nanostructures. The results compare well with previous nb initio a ll-electron calculations and with experimental data. The method predicts th e correct trends in the magnetic moments of Fe systems for a great variety of environments and requires a smaller computational effort than other ab i nitio methods.