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O: Fachverband Oberflächenphysik

O 92: Poster Session VII: Ultrafast electron dynamics at surface and interfaces III

O 92.4: Poster

Donnerstag, 4. März 2021, 10:30–12:30, P

Electron-phonon coupling for different stages of relaxation dynamics after ultra-short laser-excitation — •Sebastian T. Weber and Baerbel Rethfeld — Department of Physics and Research Center OPTIMAS, TU Kaiserslautern, Erwin-Schroedinger-Strasse 46, 67663 Kaiserslautern, Germany

For the excitation of metals with ultra-short laser pulses of visible light, the energy is absorbed by the electrons. Later, the energy is transferred to the phonons.

The strength of this energy transfer is determined by the electron-phonon coupling parameter. It in turn depends on a multitude of parameters, like the electronic temperature, the different stages of electronic nonequilibrium [1] and phononic properties [2].

We study the electron-phonon coupling in dependence on different states of ultra-fast dynamics after laser-excitation. First, the coupling strength is mostly determined by the electron temperature. It is also influenced by the laser-induced nonequilibrium electron distribution. With the heating of the phonons, the lattice temperature comes into play. The decreasing Debye Temperature [2] leads to a strong drop of the electron-phonon coupling strength. Moreover, the cooling of electrons by phonons induces a long-lasting nonequilibrium of the electronic system, which influences the coupling strength as well [1].

[1] S. T. Weber and B. Rethfeld, PRB 99, 174313 (2019)
[2] M. Z. Mo et al., Science 360, 1451 (2018)