The migration of Li on an (001) Ru surface was studied by using nuclear magnetic resonance techniques, with 8Li as a probe. Nuclear spin-lattice relaxation measurements, as a function of the substrate temperature and alkali metal coverage, revealed the existence of 2 distinctly different diffusion barriers on the surface; with associated energies of 0.46 and 0.22eV. The former value was attributed to jumps from steps to terrace sites, while the latter value was associated with barriers between adjacent terrace sites.

H.D.Ebinger, H.J.Jänsch, C.Polenz, B.Polivka, W.Preyss, V.Saier, R.Veith, D.Fick: Physical Review Letters, 1996, 76[4], 656-9