Results of step fluctuation experiments for Mo(011), using low-energy electron microscopy, were re-examined using recently developed procedures that offer accurate coefficients of surface mass diffusion. By these means, surface diffusion Ds was documented at homologous temperatures of about 0.5, while a cross-over to relaxation driven by bulk vacancy diffusion was deduced to occur at homologous temperatures of about 0.6 (for Tm = 2896K). The relationship,

D (cm2/s) = 4 x 10-4 exp[-1.13(eV)/kT]

was obeyed at 1080 to 1680K. Possible indications of diffusion along step edges appeared at homologous temperatures of about 0.4. The same measurements of step fluctuation amplitudes also determined the step stiffness which, by symmetry, was anisotropic on Mo(011). It was shown that 3 independent procedures yielded mutually consistent step stiffness anisotropies. These were (1) step fluctuation amplitudes; (2) step relaxation rate anisotropies; and (3) the observed anisotropies of islands in equilibrium on the Mo(011) surface. The magnitude of the step stiffness obtained from step edge relaxation was consistent with earlier measurements that determine diffusion from grain boundary grooving.

Surface Mass Diffusion and Step Stiffness on an Anisotropic Surface; Mo(011). M.Ondrejcek, W.Swiech, C.P.Flynn: Surface Science, 2006, 600[20], 4673-8