Using the spectroscopy of step-edge fluctuations observed by low-energy electron microscopy, measurements were made of the stiffness of surface steps on Nb(011) thin single-crystal films as a function of step orientation. From this was also determined a step free-energy (line-tension) of about 0.320eV/nm. The results were supported by the observed equilibrium shapes of islands on the surface. The measured parameters were used to analyze the configurations of nanostructures. Firstly, for the glide of a threading edge dislocation through a field of parallel steps, the maximum absolute plucking force exerted on the step by the dislocation was determined to be about 75pN. Secondly, from the observed equilibrium of steps with facets, the free energy with which step-edges bonded to the <111> edges of {011} facets was deduced to be 0.027eV/nm.

From Step Fluctuations to Nanostructure Energetics on Nb(011). M.Ondrejcek, W.Swiech, C.P.Flynn: Philosophical Magazine, 2006, 86[10], 1387-400