Münster 1997 – wissenschaftliches Programm

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O: Oberflächenphysik

O 15: Raster-Kraft-Mikroskopie II

O 15.2: Vortrag

Dienstag, 18. März 1997, 09:45–10:00, BOT

True atomic resolution on the surface of an insulator via ultrahigh vacuum dynamic force microscopy — •M. BAMMERLIN, R. LÜTHI, E. MEYER, J. LÜ, M. GUGGISBERG, T. LEHMANN, L. HOWALD, and H.-J. GÜNTHERODT — Institut für Physik Universität Basel Klingelbergstrasse 82
CH-4056 Basel Schweiz.

We report for the first time how true atomic resolution can systematically be obtained via non-contact dynamic force microscopy in ultrahigh vacuum on the surface of an insulator. In addition to the periodic atomic arrangement of the NaCl(001) cleavage face, single atomic-scale defects have been observed over several hours before and after an atomic jump. The non-monotonic variation of the resonance frequency shift Δ f of the oscillating cantilever reveals the narrow distance range where such measurements are possible. Observed maxima in the topography at constant negative Δ f are tentatively assigned to cations on the basis of recent calculations. Simultaneously recorded atomic scale variations of the cantilever damping are attributed to the local excitation of acoustic phonons. By making the structure and the slow dynamics of defects on insulating surfaces accessible, such experiments open up a new avenue in the surface science of wide-bandgap materials.