Effect of kink-rounding barriers on step edge fluctuations |
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Authors: | Jouni KallunkiJoachim Krug |
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Institution: | Fachbereich Physik, Universität Essen, 45117 Essen, Germany |
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Abstract: | The effect that an additional energy barrier Ekr for step adatoms moving around kinks has on equilibrium step edge fluctuations is explored using scaling arguments and kinetic Monte Carlo simulations. When mass transport is through step edge diffusion, the time correlation function of the step fluctuations behaves as C(t)=A(T)t1/4. At low temperatures the prefactor A(T) shows Arrhenius behavior with an activation energy (Edet+3?)/4 if Ekr<? and (Edet+Ekr+2?)/4 if Ekr>?, where ? is the kink energy and Edet is the barrier for detachment of a step adatom from a kink. We point out that the assumption of an Einstein relation for step edge diffusion has lead to an incorrect interpretation of step fluctuation experiments, and explain why such a relation does not hold. The theory is applied to experimental results on Pt(1 1 1) and Cu(1 0 0). |
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Keywords: | Models of surface kinetics Atomistic dynamics Surface diffusion Stepped single crystal surfaces Monte Carlo simulations |
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