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O: Fachverband Oberflächenphysik
O 56: Scanning probe techniques: Method development II
O 56.2: Vortrag
Mittwoch, 11. März 2026, 10:45–11:00, HSZ/0401
High spatial resolution of Si(111)-7x7 using LFM with a CO-tip — •Shinjae Nam1,2, Thomas Holzmann1, Franz Giessibl1, and Alfred Weymouth1 — 1University of Regensburg, Regensburg, Germany — 2Center for Quantum Nano Science, Seoul, South Korea
The Si(111) 7x7 reconstructed surface has long served as an iconic benchmark for proving the capabilities of scanning probe microscopes. Since STM first resolved the 7x7 pattern in 1983, advances in frequency-modulation AFM have enabled true atomic resolution and quantitative access to short-range chemical and frictional interactions. In this work, we report unprecedented atomic resolution and quantitative mapping of site-dependent lateral forces on the Si(111) 7x7 surface using a qPlus-based lateral force microscope. The tip is terminated with a CO molecule, and oscillating laterally with an amplitude of 50 pm. Unlike reactive Si tips, the CO tip provides a chemically inert and well-defined probe apex, enabling exceptionally sharp contrast and resolving subtle differences between faulted and unfaulted half-cells. The measured lateral force maps agree quantitatively well with theoretical models. These results establish CO-tip LFM as a powerful technique for probing lateral interactions with single-atom precision.
Keywords: Scanning probe microscopy; Semiconductor; Functionalized tip; Lateral force; Atomic force