Berlin 2024 – scientific programme

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O: Fachverband Oberflächenphysik

O 36: Poster: Ultrafast Electron Dynamics at Surfaces and Interfaces

O 36.4: Poster

Tuesday, March 19, 2024, 18:00–20:00, Poster C

Laser-induced ultrafast electron dynamics based on a two-band model — •Stephanie Roden, Tobias Held, Sebastian T. Weber, and Bärbel Rethfeld — Department of Physics and Research Center OPTIMAS, RPTU, Kaiserslautern-Landau

After an ultrashort laser excitation, the energy of an optical laser pulse is absorbed by the electrons of a solid. The thermalization of the excited electron system and the relaxation with the phonons to a joint temperature can be calculated in a kinetic manner by coupled Boltzmann collision integrals.

Previous implementations are based on an effective one-band model for the electron system [1]. This approximation does not allow a distinction between intra- and interband relaxation within the electron system. However, a separate consideration of these relaxation processes can strongly influence calculated optical parameters [2] as well as the electron-phonon coupling [3]. In this work, we extend the existing one-band model to an energy-resolved two-band model for a thin gold film that distinguishes between free sp- and more localized d-electrons. We show selected results of the intertwined relaxation dynamics following an ultra-short laser pulse.

[1] B. Y. Mueller and B. Rethfeld, PRB 87, 035139 (2013)

[2] P. D. Ndione, S. T. Weber, D. O. Gericke and B. Rethfeld, Sci. Rep. 12, 4693 (2022)

[3] T. Held, S. T. Weber, and B. Rethfeld, arXiv:2308.01067 (2023)

Keywords: Ultrashort laser excitation, Boltzmann equation