Thickness dependence of structure stability of Co/Cu(100) superlattices

The electronic structures and stability of Co/Cu(100) superlattices have been investigated by a first-principles method based on density functional theory. The models 3Co/xCu (x = 1-8 monolayers) with different Cu layer thicknesses are investigated. The result shows that the stability increases with an increase in Cu layer thickness for odd (or even) Cu layer models. Thecharge transfer is prominent at the Co-Cu interface; the magnetic moment of atoms at the interfaces is larger than that of the interior Co layers, and the nonmagnetic Cu layer at the interface is slightly spin polarized under the influence of the ferromagnetic Co layers in the neighborhood. Finally, the Fermi energy, densities of states and structural energy are also discussed.