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  Session:
  Paper Type: Poster
  Title: Coalescence of Tip Induced Vacancy Islands on Ag (111) Surfaces
  Meeting: 2007 AAPT Summer Meeting: Greensboro, NC
  Location: N/A
  Date: Sunday, Jul.29
  Time: 6:30PM - 8:00PM
  Author: Andrew P Lange, Clemson University
(559)786-7500, alange@ucsc.edu
  Co-Author(s): Chad E Sosolik, Russell E Lake
  Abstract: We are investigating a new method to control the creation of vacancy-adatom island pairs by crashing an electrochemically etched tungsten tip of a scanning tunneling microscope (STM) into a silver surface. Previous stochastic experiments have employed an ion sputtering technique for pair creation that verifies the statistical (Brownian) motion that we observe for our vacancy islands. Following pair creation, the adatom islands diffuse into the silver surface with expected theoretical diffusion characteristics. The vacancy islands however, maintain their areas while diffusing horizontally along the surface even while undergoing coalescence of multiple vacancies. Coalescence events are governed by a chemical potential along the perimeter of the islands which results in an exponential equilibration of the resultant island toward the hexagonal configuration expected for an Ag (111) surface. We are probing these events using the tip crash creation method while further examining the dependence of the stabilization time on the multi-tiered properties of vacancy islands.
  Footnotes: References: 1. J. Amar and F. Family, Phys. Rev. B 52 (1995), p. 13801 2. S. Rousset, S. Gauthier, O. Siboulet, J.C. Girard, S.d. Cheveign√©, M. Huerta-Garnica, W. Sacks, M. Belin and J. Klein, Ultramicroscopy 42?44 (1992), p. 515 3. J. Krug, P. Politi and T. Michely, Phys. Rev. B 61 (2000), p. 14037 4. H.J.W. Zandvliet, R. Van Moere and B. Poelsema, Phys. Rev. B 68 (2003), p. 073404

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