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O: Fachverband Oberflächenphysik
O 99: Ultrafast Electron Dynamics IV
O 99.4: Vortrag
Freitag, 21. März 2025, 11:15–11:30, H11
Ultrafast Nonequilibrium Dynamics of Room Temperature Charge Density Wave Fluctuations in 1T-TiSe2 — •Hibiki Orio1, Samuel Beaulieu2, Sarath Sasi2, Akib Jabed2, Muthu P.T. Masilamani1, Maximilian Ünzelmann1, Jan Minar3, Friedrich Reinert1, Kai Rossnagel4, Sotirios Fragkos2, and Jakub Schusser1,3 — 1Universität Würzburg, Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence, Würzburg, Germany — 2Université de Bordeaux - CNRS - CEA, CELIA, Talence, France — 3New Technologies-Research Center, University of West Bohemia, Pilsen, Czech Republic — 4Institute of Experimental and Applied Physics, Kiel University, Kiel, Germany
TiSe2 exhibits a 2×2×2 charge density wave (CDW) phase below 200 K, driven by the interplay between electron-hole and electron-lattice interactions. Nanoscale CDW domains, referred to as CDW fluctuations, persist even above the transition temperature. This exotic phase provides an intriguing platform for exploring the robustness of electron-hole interactions and electron-phonon coupling at elevated temperatures. Using time- and polarization-resolved XUV momentum microscopy, we investigate CDW fluctuations in TiSe2 and their ultrafast light-induced dynamics. Our band structure mapping reveals that the backfolded Se 4p band associated with the CDW phase remains detectable even at room temperature. Furthermore, we demonstrate the ultrafast melting of these CDW fluctuations on an electronic timescale, followed by rapid recovery modulated by coherent amplitude phonon modes.
Keywords: time-resolved ARPES; TiSe2; charge density wave