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O: Fachverband Oberflächenphysik

O 44: Scanning probe techniques: Method development – Poster

O 44.2: Poster

Dienstag, 10. März 2026, 14:00–16:00, P2

Upgrading an LT-STM with a qPlus-AFM system — •René Knispel, Patrick Härtl, and Matthias Bode — Physikalisches Institut, Experimentelle Physik 2, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany

The invention of the scanning tunneling microscope (STM) by Binnig and Rohrer in 1981 enabled direct imaging of atomic-scale structures in real space [1]. Shortly thereafter, the recognition of tip–sample interactions enabled the development of the atomic force microscope (AFM) [2]. In 1995, Giessibl achieved true atomic resolution with AFM [3] by measuring the force gradient-induced resonance frequency shifts of a silicon cantilever. Quartz-based cantilevers with enhanced stiffness and sensitivity enabled the development of the so-called qPlus-AFM technique, which surpasses STM in spatial resolution and allows STM measurements to be performed concurrently.

To extend the capabilities of our low-temperature STM, we upgraded it with a qPlus-AFM system. The Pan-type scanner was redesigned to enable cantilever excitation and to integrate both differential oscillation signals and the STM tunneling current. A UHV-LT preamplifier for the oscillation signals was also build and mounted inside the liquid-helium shield of the cryostat. The technical implementation and performance of the upgraded microscope will be demonstrated using suitable test samples.
[1] G. Binnig et al., Phys. Rev. Lett. 49, 57 (1982).
[2] G. Binnig et al., Phys. Rev. Lett. 56, 930 (1986).
[3] F. J. Giessibl, Science 267, 68 (1995).

Keywords: qPlus AFM; Home-built; UHV; STM