We have simulated a semi-infinite system of cobalt fcc with (100) or (111) surface. The self-consistent calculations provide the layered resolved spin and orbital atomic moments, see Fig. 6.5. This allows us to establish that there exists an increment of the spin and orbital moments on the cobalt surface and the increment is sensitive to the surface type. Both the spin and the orbital magnetic moments are smaller in the case of the surface (111) than those in the case of the surface (100).
It is well known that the orbital moments of a delocalized state closely depend on the shape and the width of the density of states (DOS). The main reason for an increment of the orbital and spin moments at the surface is the modification of DOS . This can have different origins as for example: