It was noted that Co grew on W(110) in close-packed layers with hexagonal close-packed and face-centered cubic stackings. During further growth, the corresponding stacking faults resulted in dislocations at the boundaries of coalescing islands. Using scanning tunnelling spectroscopy, it was possible to distinguish between different types of dislocation which, in turn, were related to dislocation types modelled using hard spheres. In contrast to the hard sphere model, the dislocations in the Co film extended over several unit cells. Therefore, the average atomic density became the main distinguishing parameter. The change of the electronic structure in the dislocation with respect to homogeneous films was characterized by a shift of electronic states towards higher binding energy.

Scanning Tunneling Spectroscopy of Dislocations in Ultrathin FCC and HCP Co Films. M.Pratzer, H.J.Elmers: Physical Review B, 2005, 72[3], 035460 (8pp)