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O: Fachverband Oberflächenphysik
O 22: Surface dynamics – Poster
O 22.3: Poster
Montag, 9. März 2026, 18:00–20:00, P2
Non-equilibrium phonon dynamics of the kagome metal CsV3Sb5 — •Felix Kurtz1,2, Lukas Jehn1,2, Alp Akbiyik1,2, Matthieu Le Tacon3, Amir-Abbas Haghighirad3, and Claus Ropers1,2 — 1Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, D-37077 Göttingen — 24th Physical Institute, University of Göttingen, D-37077 Göttingen — 3Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, D-76021 Karlsruhe
Tracking the equilibration processes that follow photoexcitation in materials can reveal couplings between and among electrons and lattice degrees of freedom. Thus, a variety of femtosecond electron or X-ray diffraction techniques are used to follow non-equilibrium structural dynamics. Recently, we have introduced ultrafast low-energy electron diffuse scattering (ULEEDS), a surface-sensitive method capable of tracing momentum-dependent phonon populations with out-of-plane polarization [1]. Here, we employ ULEEDS to a second material, the kagome metal CsV3Sb5, and reveal non-thermal phonon occupations whose subsequent equilibration is driven by phonon-phonon scattering. Comparing these results to our previous study of TiSe2, we find that while a rapid buildup near the Brillouin-zone boundary still precedes a slower emergence of zone-center acoustic modes, the relaxation times in CsV3Sb5 are confined to a much narrower distribution.
[1] F. Kurtz et al., Nat. Mater. 23, 890-897 (2024)
Keywords: ultrafast electron diffraction; ultrafast electron diffuse scattering; kagome metal; phonon dynamics; anharmonic phonon scattering