Berlin 2024 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 13: Ultrafast Electron Dynamics at Surfaces and Interfaces II

O 13.8: Vortrag

Montag, 18. März 2024, 17:00–17:15, MA 041

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

When a metal is irradiated with an ultrashort laser pulse, the initially Fermi-distributed electrons are excited to a state far from equilibrium. These hot electrons can be exploited for numerous processes and applications, such as photodetection, solar energy conversion, and photocatalysis. However, the non-thermal electrons rapidly thermalize by collisions with each other, thereby limiting their availability for specific applications. Thus, it is crucial to understand the microscopic processes that determine the timescales of hot electron thermalization.

Here, we use a kinetic model based on full Boltzmann collision integrals to trace the non-equilibrium dynamics of the electronic distribution function during excitation and thermalization. We evaluate the time-dependent electron densities in various energy intervals and show the dependence of the dynamics of these spectral electron densities on the excitation conditions. We find energy regions where the interplay between primary and secondary electron generation leads to a behavior revealing a long-lasting non-equilibrium that cannot be explained with a single relaxation time [1].
[1] C. Seibel et al., J. Phys. Chem. C (2023),

    DOI: 10.1021/acs.jpcc.3c04581

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