Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 33: Symposium: Frontiers of Surface Sensitive Electron Microscopy I (Invited Speakers: James Hannon, Raoul van Gastel, Thomas Schmidt)

O 33.1: Hauptvortrag (ohne Erstattung)

Dienstag, 26. Februar 2008, 13:45–14:15, MA 005

Dynamics at Strained Surfaces — •James B. Hannon — IBM T.J. Watson Research Center, Yorktown Heights, NY 10598, USA

It has long been recognized that surface stress influences surface morphology and kinetics. For example, stress can drive the spontaneous formation of periodic patterns. Analysis of the equilibrium configuration of stress domains can be used to determine surface thermodynamic parameters [1]. However, in many (if not most) systems, reaching equilibrium in experiment can be difficult. In this talk, I will describe experiments in which surface thermodynamic parameters are determined by analyzing the motion of stress domains far from equilibrium. In the first example, step motion on Si(100) is used to determine the strain pattern of a dislocation that intersects the surface [2]. In the second example, the rapid growth of isolated 7x7 domains on Si(111) is described. I show how certain generic features of the domain growth (e.g., faceting) are related to the orientational dependence of the domain boundary free energy.

Work performed with R.M. Tromp (IBM) and V.B. Shenoy (Brown

Univ).

[1] Science 295 (2002) 299; Nature Materials 3 (2004) 95.

[2] Science 313 (2006) 1266.