Dresden 2026 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 44: Scanning probe techniques: Method development – Poster

O 44.3: Poster

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

Multifrequency Tunnelling Spectroscopy — •Gleb Neplyakh, Philipp E.J. Maier, Carolina A. Marques, Berk Zengin, Kevin Hauser, Rian Ligthart, Alexander LaFleur, and Fabian D. Natterer — Department of Physics, University of Zurich, Winterthurerstrasse 190, CH-8057, Switzerland

Scanning tunnelling spectroscopy (STS) probes the local density of states by measuring differential conductance as a function of energy. Traditional STS acquires N energy points by sweeping a DC bias with a small modulation superimposed. This requires N sequential measurements, making it impractical for large mapping tasks.

We have developed Parallel Spectroscopy (PS) to overcome this limitation. PS exploits the nonlinearity in the I(V) curve of the materials: a single or multitone AC voltage drive generates a set of higher harmonics that encode the full spectrum. Demodulating N harmonics within one leakage-free integration window enables the energy dependence to be recovered in a single measurement, providing substantial speedups.

We compare conventional STS and single- and multi-frequency PS with respect to signal-to-noise ratio, potential artefacts, and spectral resolution. Using PS in conjunction with compressive sensing could allow us to conduct high-resolution studies of many-body effects in quantum materials.

Keywords: Scanning tunneling microscopy; Scanning tunneling spectroscopy; quasiparticle interference; multifrequency excitation; local density of states