Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 74: Ultrafast Electron and Spin Dynamics at Interfaces

O 74.7: Poster

Mittwoch, 9. März 2016, 18:15–20:30, Poster A

Mutual influence of relaxation processes in laser-irradiated metals — •Kai Klein, Sebastian Weber, and Baerbel Rethfeld — Fachbereich Physik und Forschungszentrum OPTIMAS, TU Kaiserslautern, Germany

When an ultrashort laser pulse irradiates a metal, energy is absorbed by the electron system which is driven out of thermal equilibrium on a femtosecond time scale. Due to electron-electron collisions a new thermodynamical equilibrium state within the electron system is established in a characteristic time, the so-called thermalization time. At the same time, electron-phonon collisions transfer energy to the phononic system until both temperatures equilibrate.

We study the dynamics of the nonequilibrium systems by applying complete Boltzmann collision integrals to describe the transient electron distribution due to excitation, thermalization and relaxation. Specific material properties enter the calculation through the density of states.

The results show the mutual influence of both collision processes. We see that the coupling to the phonons affects the electron thermalization. Moreover, the electron-phonon coupling strength differs from the equilibrium coupling, when the electron system is not thermalized.