J. Phys. Colloques
Volume 50, Number C8, Novembre 198936th International Field Emission Symposium
|Page(s)||C8-253 - C8-258|
J. Phys. Colloques 50 (1989) C8-253-C8-258
STRUCTURE DETERMINATION OF Ir(111) AND (110) SURFACES BY FIELD ION MICROSCOPYO. SCHÜTZ et K. MÜLLER
Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, Erwin-Rommel-Strasse 1, D-8520 Erlangen, F.R.G.
Single W-adatom diffusion on Ir (111) and (110) surfaces, prepared by field evaporation, was used to determine the structure of these surfaces. Each adatom can be localized by a video analyzer which automatically stores the coordinates of the center of intensity. By mapping the adatom spot position after every activation cycle ( T~200K, t=20sec ) a pattern of adsorption sites was generated. This map is taken as an image equivalent to the surface order. It turned out that both surfaces reveal the (1x1) structure. While the migration on the (111) plane was essentially isotropic, prefered diffusion along  was observed on (110) surfaces. Unexpectedly the single adatoms on Ir(110) adsorbed at on-top position as determined by comparison with edge positions.