AVS 52nd International Symposium
    Surface Science Thursday Sessions
       Session SS1-ThA

Paper SS1-ThA1
Living on the Edge: Life and Death of Vacancies in Cu(100)

Thursday, November 3, 2005, 2:00 pm, Room 202

Session: Transport and Structural Stabilization of Surfaces
Presenter: K. Schoots, Leiden University, The Netherlands
Authors: K. Schoots, Leiden University, The Netherlands
M.J. Rost, Leiden University, The Netherlands
J.W.M. Frenken, Leiden University, The Netherlands
Correspondent: Click to Email
We have used STM to investigate where surface vacancies originate and annihilate on Cu(100). Because of the extremely high mobility of the surface vacancies, we have been forced to use tracer particles to follow the vacancy motion, in the form of In atoms, incorporated in the top layer. The "slide-puzzle"- diffusion of the vacancies makes the In atoms move through the surface, as has been reported in.@footnote 1-3@ In the present study, we have employed tailor-made geometries, in which the In atoms were surrounded exclusively by upward or by downward steps. Our STM movies show a striking difference between these two cases, with differences in jump frequencies and average jump lenghts of more than one order of magnitude. These results show that vacancies are primarily created at the upper side of a step and can be formulated in analogy with the energetics of ad-atoms, in terms of an Ehrlich-Schwoebel barrier@footnote 4@ for surface vacancies. @FootnoteText@ @footnote 1@ R. van Gastel et al., Nature 408 (2000) 665, Phys. Rev. Lett. 86 (2001) 1562, Surf. Sci 521 (2002) 10, Surf. Sci. 521 (2002) 26.@footnote 2@ M.L. Grant et al., Phys. Rev. Lett. 86 (2001) 4588.@footnote 3@ R. van Gastel et al., The Chemical Physics of Solid Surfaces, vol. 11, Surface Dynamics, ed. D.P. Woodruff, (Elsevier, Amsterdam, 2003), p. 351-370.@footnote 4@ G. Ehrlich et al., J. Chem. Phys. 44 (1966) 1039.