Berlin 2024 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

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

O 36.10: Poster

Dienstag, 19. März 2024, 18:00–20:00, Poster C

Dynamics of energy-resolved electron densities at the non-thermal stage in gold — •Markus Uehlein, Christopher Seibel, Tobias Held, Sebastian T. Weber, and Baerbel Rethfeld — Department of Physics and Research Center OPTIMAS, RPTU Kaiserslautern-Landau

During femtosecond laser excitation, the electron distribution in a metal is disturbed to a state far from equilibrium, i.e. far from a Fermi distribution. The resulting high-energy electrons (hot electrons), e.g., drive chemical reactions at surfaces and are utilized in biosensing methods. An important step for further studies is to understand how many electrons exist in a specific energy range and on what timescale. This is measurable for example with photoemission experiments.

We apply a kinetic model based on full Boltzmann collision integrals to trace dynamics of the electronic distribution [1]. Thereby, the different processes contributing to excitation and thermalization can be investigated independently. We study the temporal evolution of the electron densities in various energy ranges, pointing out the influence of primary and secondary electron generation [2]. Furthermore, we compare the microscopic description of the electron-electron scattering with a relaxation time approach and an extended temperature-based description.

[1] B.Y. Mueller, B. Rethfeld, Phys. Rev. B 87, 035139 (2013)

[2] C. Seibel, M. Uehlein et al., J. Phys. Chem. C (2023)

        DOI: 10.1021/acs.jpcc.3c04581

Keywords: non-thermal electrons; femtosecond laser excitation; ultrafast electron dynamics