AVS 50th International Symposium
    Surface Science Wednesday Sessions
       Session SS-WeP

Paper SS-WeP23
Step Edge Diffusion on Ag: Correlations and Persistence as a Function of Temperature*

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: O. Bondarchuk, University of Maryland
Authors: O. Bondarchuk, University of Maryland
M. Degawa, University of Maryland
E.D. Williams, University of Maryland
D.B. Dougherty, University of Maryland
M. Constantin, University of Maryland
S. Das Sarma, University of Maryland
C. Dasgupta, University of Maryland
Correspondent: Click to Email
The stochastic character of step-edge diffusion can be evaluated in terms of the persistence probability for step edge fluctuation, that is the probability that a fluctuating step does not return to a chosen initial position over a given time interval. Time dependent STM was used to observe temporal step fluctuations on Ag(111) thin film in temperature range from RT up to 450 K. The concept of persistence@footnote 1,2@ as well as the more usual time-correlation function have been used to analyze the step edge fluctuation on the surface in equilibrium and under electrical current stress. Experimentally measured persistence scales as a simple power law that is consistent with scaling predictions,@footnote 1@, and which also agrees with more rigorous tests of persistent behavior.@footnote 3@ The temperature dependence of the persistence prefactor is extremely weak, in contrast with the (diffusion constant dominated) Arrhenius behavior of the prefactor of the correlation function. Numerical calculations using the continuum Langevin equation confirm the weak temperature dependence. The physical significance of the persistence prefactor and the effects of discrete sampling and electrical current stress will be discussed. *This work has been supported by the NSF-NIRT and NSF-MRSEC. @FootnoteText@@footnote 1@J.Krug, H. Kallabis, S.N. Majumdar, S.J.Cornell, A.J. Bray, C.Sire, Phys.Rev. E56(1997)2702. @footnote 2@ D.B. Dougherty, O. Bondarchuk, M.Degawa, E.D. Williams, Surf.Sci. 527(2003)L213. @footnote 3@ M. Constantin, S.Das Sarma, C. Dasgupta, O.Bondarchuk, D.B. Dougherty, E.D. Williams, in press.