Magnetic structure of vanadium overlayers on semi-infinite Nb substrate

We investigate the magnetic ordering of V/Nb systems using a real space tight-binding approach. The magnetism is described in the unrestricted Hartree-Fock approximation of the Hubbard Hamiltonian. The density of states has been calculated within the recursion technique. The magnetic moments of V-n/Nb system with n = 1-3 for different crystallographic directions {(0 0 1), (0 1 1), (1 1 1)} have been calculated. The onset of magnetism depends strongly on the faces considered. Magnetism is more pronounced for the (0 0 1) surface and is found to decrease when V is allowed to relax in order to recover its bulk volume. The magnetic moments of the surface layers are strongly enhanced by addition of more V layers. A sizable induced moment appears in the Nb interface layer which decreases by addition of more V layers.