Münster 1997 – wissenschaftliches Programm
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O: Oberflächenphysik
O VII: HV VII
O VII.1: Hauptvortrag
Donnerstag, 20. März 1997, 09:30–10:15, S 10
“STEP DANCING”: SURFACE DYNAMICS STUDIED WITH HOT STM MOVIES — •J.W.M. Frenken1,2, M.S. Hoogemann2, M.F. Chang2, and M.A.J. Klik2 — 1Kamerlingh Onnes Laboratory, University of Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands — 2FOM-Institute for Atomic and Molecular Physics, Kruislaan 407, NL-1098 SJ Amsterdam, The Netherlands
Dynamic surface processes play a key role in phase transitions, step fluctuations, growth phenomena, the evolution towards the crystal equilibrium shape and other surface properties. In order to follow surface dynamics on the atomic scale over a wide range of temperatures, we have developed a special, "temperature-programmed" scanning tunneling microscope. The instrument keeps a particular area on a metal surface "in view" during significant changes in specimen temperature of several hundred degrees.
We employ the STM to record high-speed movies of the creation, annihilation, and diffusion dynamics of surface defects, such as steps and kinks. From a statistical analysis of the images and the differences between subsequent images, we derive the formation and interaction energies of these defects and the activation energies for their motion.
At sufficiently high temperatures, steps proliferate and cause surfaces to become rough. This phase transition is "seen" directly in our high-temperature STM observations.