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O: Fachverband Oberflächenphysik

O 54: Scanning Probe Microscopy: Light Matter Interaction at Atomic Scales I

O 54.8: Talk

Wednesday, March 20, 2024, 17:15–17:30, MA 041

Combining THz Pump-Probe spectroscopy with Scanning Tunneling Luminescence — •Kurt Lichtenberg, Johannes Schust, Felix Huber, Susanne Baumann, and Sebastian Loth — University of Stuttgart, Institute for Functional Matter and Quantum Technologies, Stuttgart, Germany

Inelastic electron tunnelling in scanning tunnelling microscopes (STM) can trigger atomically-localized emission of light from metallic tunnel junctions, molecules or semiconducting surfaces. This enables studies of light-matter interaction at sub-molecular length scales. Fast gating of the tunnelling current by pulsed voltage sources gives access to the dynamics of the underlying excitation and light emission processes. Electronic pulse generators provide nanosecond time resolution [1], but much faster voltage transients are possible by exciting the STM's tunnel junction with single-cycle THz pulses, which were shown to generate electroluminescence [2]. We combine THz excitation [3] with single-photon detection in a variable-temperature STM and investigate the possibilities for ultrafast and atomically resolved measurements of electroluminescence using THz pump-probe spectroscopy.

[1] C. Grosse, et al. Appl. Phys. Lett. 103 183108 (2013)

[2] K. Kimura, et al. ACS Photonics 8 982 (2021)

[3] M. Abdo, et al. ACS Photonics 8 702 (2021)

Keywords: THz; STM; Luminescence; Ultrafast; Electroluminescence