Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 59: Complex Oxides Interfaces and Charge Order
TT 59.6: Vortrag
Donnerstag, 4. April 2019, 16:15–16:30, H22
High-harmonic spectroscopy of the charge-density wave transition in 1T-TiSe2 — •Tobias Heinrich1, Sergey Zayko1, Murat Sivis1, Kai Rossnagel2, Ofer Kfir1, and Claus Ropers1 — 14th Physical Institute - Solids and Nanostructures, University of Göttingen, Germany — 2Institute for Experimental and Applied Physics, University of Kiel, Germany
Correlated materials exhibit a wide variety of intriguing ordering phenomena, such as the charge-density wave (CDW) state in layered transition-metal dichalcogenides. The charge-density at the transition metal site and the CDW-induced band structure changes can be probed by photoemission spectroscopy [1,2]. However, also near-edge optical and x-ray spectroscopy of core-levels should provide valuable time-resolved information.
Here, we employ an extreme-ultraviolet pump-probe setup to study the CDW-to-normal phase transition in 1T-TiSe2. Our setup features femtosecond infrared pump and high-harmonic (25−50 eV ) probe pulses, suitable to access CDW-features near the Ti M-edge. In our experiments, we find characteristic spectral changes upon thermally inducing the phase transition near 202 K, which are indicative of a splitting of the Ti-M edge into nonequivalent Ti sites. In ongoing experiments, we investigate the temporal evolution of the spectral signatures with a temporal resolution below 40 fs, complementing ultrafast photoemission spectroscopy studies.
Timm Rohwer et al., Nature 471, 490-493 (2011)
S. Hellmann et al., PRL 105, 187401 (2010)