IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Wednesday Sessions
       Session SS1-WeM

Paper SS1-WeM3
Nothing Moves a Surface: Probing Surface Vacancy Dynamics with a Surface Alloy

Wednesday, October 31, 2001, 9:00 am, Room 120

Session: Surface Diffusion
Presenter: R. Van Gastel, Universiteit Leiden, The Netherlands
Authors: R. Van Gastel, Universiteit Leiden, The Netherlands
E. Somfai, Universiteit Leiden, The Netherlands
S.B. Van Albada, Universiteit Leiden, The Netherlands
W. Van Saarloos, Universiteit Leiden, The Netherlands
J.W.M. Frenken, Universiteit Leiden, The Netherlands
Correspondent: Click to Email
Indium atoms that are deposited on the Cu(001) surface at room temperature rapidly diffuse to steps where they are incorporated into the first layer of the crystal surface. We use the In/Cu(001) surface alloy to probe the dynamics of surface vacancies. The motion of embedded indium atoms enables us to use these atoms as `tracer' particles for the direct visualization of vacancy mediated diffusion of surface atoms.@footnote 1@ Steps on the surface act as sources and sinks for surface vacancies. This crucial role of steps is exposed as the mobility of embedded indium atoms is spatially mapped out. The temperature dependence of the diffusion of embedded indium atoms is investigated through high speed STM movies. The temperature dependence provides us with a direct measurement of the surface vacancy mobility, and yields the sum of the vacancy formation and migration energies. In addition to this, we present first results from experiments, in which monatomic surface vacancies are artificially created. From these the vacancy migration energy can be obtained so that we can experimentally separate out the formation and migration energies. @FootnoteText@ @footnote 1@R. van Gastel et al., Phys. Rev. Lett. 86 (2001), 1562.