IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Friday Sessions
       Session SS3-FrM

Paper SS3-FrM3
In-Situ STM Study of the Au(111) Herringbone Reconstruction Under Applied Stress

Friday, November 2, 2001, 9:00 am, Room 122

Session: Clean and Adsorbed Surfaces
Presenter: A.K. Schmid, Lawrence Berkeley National Laboratory
Authors: O. Schaff, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
A.K. Schmid, Lawrence Berkeley National Laboratory
N.C. Bartelt, Sandia National Laboratories
J. de la Figuera, Sandia National Laboratories
R.Q. Hwang, Sandia National Laboratories
Correspondent: Click to Email
Surface stress is generally invoked as the driving force for the remarkably well-ordered and stable dislocation networks or reconstructions found in the surface layers of many epitaxial thin films, as well as in many metal single-crystal surfaces. To test this conjecture, the effect of uniaxial applied stress on dislocation networks present in the atomic surface layer of Au(111) was studied. The measurements were made using a novel instrument combining ultrahigh vacuum scanned-probe microscopy with an in-situ stress-strain testing machine. The technique provides microscopic information, up to atomic resolution, about the large-scale plasticity of surface layers under applied loads. The herringbone reconstruction of the Au(111) surface is a classic example of a strain stabilized dislocation network. We find that under 0.5% uniaxially applied compressive strain a dramatic restructuring of the network takes place. The three-fold orientational degeneracy of the system is removed and threading edge dislocations are annihilated. By considering the energetics of the herringbone reconstruction in the context of the Frenkel-Kontorova model, we are able to explain why these changes take place at this value of the applied strain.