Münster 1997 – wissenschaftliches Programm

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O: Oberflächenphysik

O 36: Phasenübergänge und dynamische Eigenschaften

O 36.1: Vortrag

Donnerstag, 20. März 1997, 16:00–16:15, BOT

Thermal roughening of uncorrelated steps — •M.I. Larsson¹, M.C. Tringides², H. Frischat¹, and J. Wollschl"ager¹ — ¹Institut f"ur Festk"orperphysik, Universit"at Hannover, Appelstr.2, D-30167 Hannover — ²Department of Physics, Iowa State University, Ames IA 50011, USA

We study the thermal roughening of uncorrelated step edges on vicinal fcc (111) surfaces by means of kinetic Monte Carlo (MC) simulations and kinematic calculations of the diffraction profiles. Both the initial and the final local atomic environments are used in the MC model to determine the hopping probability for atoms diffusing on the surface. We found that the step-edge fluctuations are Gaussian distributed when the kink density has reached quasi-equilibrium. Deviations from the Gaussian distribution are present at early enough times because of the straight edge initial configuration. Deviations from the Gaussian distribution is also expected when the overall equilibrium over the whole surface has been established. We discuss the shapes of the resulting terrace distributions in terms of the effective step-step interactions.