Coverage-dependent collective diffusion of a dense Pb wetting layer on Si(111).
The dynamics of a dense Pb wetting layer on the Si(111) surface is studied in the framework of a generalized Frenkel-Kontorova model. Instead of the typical diffusion by random hopping processes, a liquidlike collective motion of the Pb atoms within the dense wetting layer is revealed to give rise to ultrafast kinetics of the wetting layer even at low temperatures. A kinetic Monte Carlo simulation including this collective spreading mechanism of the dense wetting layer quantitatively reproduces the experimental observations.
Ames Laboratory, US-DOE, Department of Physics, Iowa State University, Ames, Iowa 50011, USA.
Li
L
Huang
C Z
CZ
Wang
M Z
MZ
Li
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KM
Ho