It was recalled that, on the vicinal face of a crystal, a wandering instability of steps could occur under non-equilibrium conditions when asymmetry in the surface diffusion field existed. Near to the transition temperature of Si(111) surface between 1x1 and 7x7 structures, wandering instability was observed during growth. This instability was provisionally attributed to the gap in diffusion coefficient on the upper and the lower terraces whose surface structures were different. Using a linear stability analysis and Monte Carlo simulations, it was shown that the instability in growth occurred if the diffusion coefficient of the lower terrace was larger. The wandering pattern in a vicinal face was chaotic when evaporation was allowed, but was rather periodic when evaporation was absent. The latter result agreed with experimental observations.

Step Wandering due to the Gap in Diffusion Coefficient on the Upper and the Lower Terraces. R.Kato, M.Uwaha, Y.Saito, H.Hibino: Surface Science, 2003, 522[1-3], 64-74

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