It was noted that equilibrated 2-dimensional Ir islands on Ir(111) surfaces exhibited longer B steps than A steps, where A-steps were <110>/{111} and B-steps were <110>/{100}. The B steps therefore had a lower step free-energy than did A steps, contrary to previous reports.

Comment on Self-Diffusion and Dynamic Behavior of Atoms at Step Edges on Iridium Surfaces M.J.Rost, T.Michely, G.Comsa: Physical Review B, 1998, 57[3], 1992-4