Dresden 2026 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 79: Plasmonics and nanooptics: Light-matter interaction, spectroscopy III
O 79.4: Vortrag
Donnerstag, 12. März 2026, 11:15–11:30, HSZ/0403
Low temperature near-field fingerprint spectroscopy of 2D electron systems in oxide heterostructures and beyond — Julian Barnett1, Konstantin Wirth1, Richard Hentrich2, Yasin C. Durmaz2, Felix Gunkel3, Marc-Andre Rose3, and •Thomas Taubner1 — 1I. Institute of Physics (IA), RWTH Aachen University — 2Attocube Systems AG, Munich — 3PGI-7, Forschungszentrum Jülich
Scattering-type scanning near-field optical microscopy (s-SNOM) is a useful tool for the non-destructive investigation of buried confined electron systems with nanoscale resolution, however, a clear separation of carrier concentration and mobility was often not possible. Here, we predict a characteristic fingerprint response of the LaAlO3/SrTiO3 2DEG in the mid-infrared spectral range, which was not experimentally accessible in the past, and verify this using a state-of-the-art tunable narrow-band laser in cryo-s-SNOM at 8 K [1]. Our modeling allows us to separate the influence of carrier concentration and mobility on fingerprint spectra and to characterize 2DEG inhomogeneities on the nanoscale. We show that our fingerprint spectra are a universal feature and generally applicable to confined electron systems, like topological insulators or stacked van-der-Waals materials.
[1] J. Barnett et al., Nat. Comm. 16, 4417 (2025).
Keywords: s-SNOM; 2DEG; Infrared Spectroscopy; Oxides; 2D Materials