Regensburg 2022 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 9: Ultrafast Electron Dynamics at Surfaces and Interfaces 2
O 9.3: Vortrag
Montag, 5. September 2022, 15:30–15:45, H3
Electronic and phonon dynamics in 1T-TiSe2 with ultrafast core-level transient absorption spectroscopy in the extreme ultraviolet — •Tobias Heinrich1, Hung-Tzu Chang1, Sergey Zayko1, Murat Sivis1,2, and Claus Ropers1,2 — 1Max Plank Institute for Multidisciplinary Sciences, Göttingen, Germany — 24th Physical Institute - Solids and Nanostructures, University of Göttingen, Germany
Extreme ultraviolet (XUV) transient absorption spectroscopy with high harmonic sources is ideally suited to investigate the complex interplay between lattice and electronic degrees of freedom on ultrafast timescale [1]. Here, we compare the experimental result of highly sensitive XUV transient absorption spectroscopy on the charge density wave (CDW) compound 1T-TiSe2 with density functional theory (DFT) simulations to disentangle electronic and phonon contributions to the transient absorption spectra. In addition to photo excited carriers we observe two coherently excited phonon modes that can be assigned to the A1g optical mode (6 THz) and the A1g* (3.3 THz) amplitude mode associated with the CDW formation [2]. The modes show distinct spectral fingerprints which are reproduced by DFT calculations such that their dynamics can be individually analyzed. It is found that only the amplitude mode vanishes at higher fluences, corroborating the proposed mechanism of non-thermal CDW melting [3]. [1] A. R. Attar et al., ACS Nano 14, 11, 15829-15840 (2020)
[2] H. Hedayat et al., New J. Phys. 23, 033025 (2021)
[3] E. Möhr-Vorobeva et al., Phys. Rev. Lett. 107, 036403 (2011)