AVS 46th International Symposium
    Surface Science Division Wednesday Sessions
       Session SS3+NS-WeA

Paper SS3+NS-WeA5
Step Energetics of Pb(111) Vicinal Surfaces from Facet Shape

Wednesday, October 27, 1999, 3:20 pm, Room 604

Session: Islands, Clusters, and Steps
Presenter: H.P. Bonzel, Forschungszentrum Jülich, Germany
Authors: H.P. Bonzel, Forschungszentrum Jülich, Germany
K. Arenhold, Forschungszentrum Jülich, Germany
A. Emundts, Forschungszentrum Jülich, Germany
S. Surnev, Forschungszentrum Jülich, Germany
P. Wynblatt, Carnegie Mellon University
Correspondent: Click to Email
The formation energies of steps and kinks, the step stiffness and the step interaction energy of B-steps vicinal to (111) have been derived quantitatively from the equilibrium shape of small three-dimensional Pb crystallites supported on a Ru(001) surface. The crystallites were imaged by scanning tunneling microscopy and show (111) and (100) facets.@footnote 1@,@footnote 2@ The boundary of these facets is well defined in the STM images and was used to determine also the azimuthal dependence of the step free energy for vicinal (111) surfaces by employing an "inverse" Wulff construction. Taking the accepted value for the surface free energy of Pb, absolute step energetic quantities can be quoted for both A- and B-steps. The step stiffness is derived from the step curvature and the step energy. The entropic step interaction energy of B-steps at 440 K is calculated from the step stiffness. Furthermore, by taking into account the curved portion of the vicinal (111) surface normal to the direction of B-steps, which shows a Prokovsky-Talapov behavior,@footnote 2@ the total step interaction energy of B-steps is also obtained. The entropic and total step interaction energies of B-steps at 440 K are thus 2.3 meV/Å@super2@ and 7.9 meV/Å@super2@, respectively.@footnote 3@ The difference is largely attributed to the elastic dipole-dipole interaction. Calculations of the step and elastic step interaction energies using the embedded atom potential of Pb@footnote 4@ are currently underway and will be compared with the experimental data. @FootnoteText@ @footnote 1@ S. Surnev et al., J. Vac. Sci. Technol. A 16(1998)1059. @footnote 2@ K. Arenhold et al., Surf. Sci. 417(1998)L1160. @footnote 3@ K. Arenhold et al., Surf. Sci. 424(1999)271. @footnote 4@ H.S. Lim, C.K. Ong, F. Ercolessi, Surf. Sci. 269/270(1992)1109.