Regensburg 2025 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 5: Scanning Probe Microscopy: Light-Matter Interactions at the Atomic Scale I
O 5.9: Vortrag
Montag, 17. März 2025, 12:30–12:45, H6
Ultrafast manipulation of charge-density wave order with THz-STM — Shaoxiang Sheng1,2, Kurt Lichtenberg1, Susanne Baumann1, and •Sebastian Loth1,3 — 1University of Stuttgart, Institute for Functional Matter and Quantum Technologies, Stuttgart, Germany — 2Max Planck Institute for Solid State Research, Stuttgart, Germany — 3Center for Integrated Quantum Science and Technology (IQST), University of Stuttgart, Stuttgart, Germany
Charge-density wave (CDW) materials present unique opportunities for exploring the interplay between structural distortions and the collective dynamics of complex electronic phases at the atomic scale. We use terahertz spectroscopy in the scanning tunneling microscope (THz-STM) to investigate charge-order dynamics in the prototypical CDW materials 2H-NbSe2 and 1T-TaS2. By employing tip-enhanced terahertz electric fields, we directly excite phase dynamics of the charge order and probe their local electronic response by terahertz-induced electron tunneling. Our measurements show that the incommensurate CDW of NbSe2 features slow phase dynamics in the proximity of defects [1], whereas the commensurate CDW of TaS2 exhibits fast reconfigurations within individual domains. The presented spatially resolved dynamics of CDWs demonstrate how atomically localized THz excitation can be leveraged to manipulate electronic states with femtosecond temporal precision, offering insights into the fundamental mechanisms of electronic or structural phase transitions in different materials.
[1] S. Sheng, et al., Nat. Phys. 20, 1603 (2024).
Keywords: scanning tunneling microscopy; charge-density waves; terahertz spectroscopy; THz-STM