  In order to search for the magnetic ground state of surface nanostructures we
extended first principles adiabatic spin dynamics to the case of fully
relativistic electron scattering. Our method relies on a constrained density
functional theory whereby the evolution of the orientations of the spin-moments
results from a semi-classical Landau-Lifshitz equation. This approach is
applied to a study of the ground state of a finite Co chain placed along a step
edge of a Pt(111) surface. As far as the ground state spin orientation is
concerned we obtain excellent agreement with the experiment. Furthermore we
observe noncollinearity of the atom-resolved spin and orbital moments. In terms
of magnetic force theorem calculations we also demonstrate how a reduction of
symmetry leads to the existence of canted magnetic states.
