AVS 50th International Symposium
    Surface Science Monday Sessions
       Session SS3-MoM

Paper SS3-MoM10
Time-space Height Correlations of Thermally Fluctuating 2-d Systems; Application to Vicinal Surfaces and Analysis of STM Images

Monday, November 3, 2003, 11:20 am, Room 328

Session: Surface Diffusion and Wetting
Presenter: L. Barbier, CEA Saclay, France
Authors: L. Barbier, CEA Saclay, France
B. Salanon, CEA Saclay, France
E. Le Goff, CEA Saclay, France
Correspondent: Click to Email
For thermally fluctuating 2-d systems, like solid surfaces, time and space correlation of the local surface height diverge logarithmically in the rough phase, whereas saturation is obtained below the roughening transition (at T@sub R@). A 2-d Langevin formalism with matter conservation within the surface plane is presented. An overall expression for correlation functions is obtained that are related to atom hopping rates and surface stiffnesses@footnote 1@. In contrast with previous 1-d approaches of step dynamics on vicinal surfaces,@footnote 2-4@ solution of the 2-d Langevin equation for anisotropic systems gives time correlation functions G(t) depending on energetic and hopping rates in the two main directions and the influence of surface stiffnesses on surface dynamics can be emphasized. At finite times, G(t) cross over to power laws ~t^(1/n) (n = 1, 2 or 4), within limited time ranges as it was observed for isolated fluctuating steps. Limits of time ranges are related to stiffnesses and diffusion anisotropies. For long times, logarithmic divergence (T > T@sub R@ ) or saturation (T < T@sub R@) of G(t) are recovered. Applications to the analysis of STM images of vicinal surfaces are given.@footnote 1@ @FootnoteText@ @footnote 1@E. Le Goff, L. Barbier and B. Salanon, Surface Science 531(3) (2003) 337. @footnote 2@M. Giesen, Progress in Surface Science 68 (2001) p 1, and references therein. @footnote 3@A. Pimpinelli, J. Villain, D.E. Wolf, J.J. Métois, J.C. Heyraud, I. Elkinani, G. Uimin Surf. Sci. 295 (1993) 143. 4 -T. Ihle, C. Misbah, O. Pierre-Louis, Phys Rev. B 58 (1998) 2289.