Dresden 2026 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 22: Surface dynamics – Poster
O 22.1: Poster
Montag, 9. März 2026, 18:00–20:00, P2
Tracing light-induced dynamics of correlated charge order at the atomic scale — •Luis Enrique Parra Lopez1, Alkisti Vaitsi1, Vivien Sleziona1, Fabian Schulz2, Martin Wolf1, and Melanie Müller1 — 1Fritz Haber Institute, Berlin, Germany — 2CIC nanoGUNE, Donostia-San Sebastian, Spain
Terahertz-driven scanning tunneling microscopy (THz-STM) is a versatile technique that enables the study of ultrafast dynamics in quantum materials with simultaneous nanometer spatial and femtosecond temporal resolution. Here, we use THz-STM to investigate the local ultrafast response of the charge density wave (CDW) phase in 1T-TaS2. Optical-pump THz-probe measurements reveal coherent oscillations of the THz-driven tunneling current at 2.5 THz, consistent with the amplitude mode of the CDW. In addition, we observe a previously unreported 1.3 THz mode in the vicinity of a structural defect, consistent with predictions for interlayer phonons. Beyond these ultrafast collective dynamics, our measurements uncover an additional slower effect: THz-induced long-lived changes of the local density of states (LDOS). These metastable modifications appear as LDOS peak shifts indicative of local stacking changes. They do not arise from the coherent CDW response, but from a local THz-induced perturbation of the CDW lattice. We demonstrate that these changes appear predominantly near lattice inhomogeneities and are consistent with local misalignments of the stacking configuration. Together these findings highlight THz-STM as a platform for imaging and controlling nonequilibrium quantum phases at their intrinsic spatial and temporal scales.
Keywords: Coherent Phonons; Ultrafast STM; THz-STM; Charge Density Wave; TaS2