Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 58: Poster Session III (Solid-liquid interfaces; Scanning probe and other methods; Electronic structure theory; Spin-orbit interaction)

O 58.29: Poster

Mittwoch, 13. März 2013, 18:15–21:45, Poster B1

Relaxation dynamics in laser-excited metals under non-equilibrium conditions — •Benedikt Y. Mueller and Bärbel Rethfeld — Technical University 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 timescale. 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. The absorbed energy of the electrons will be further transferred to the phononic system. The thermalization time as well as the electron-phonon coupling strength [1] both strongly depend on the material properties and the excitation type. Furthermore, a non-thermalized electron gas couples differently to the phononic system as a thermalized one [2]. In order to follow the relevant microscopic dynamics without the need to assume thermalized electrons, we apply complete Boltzmann collision integrals to describe the transient electron distribution due to excitation, thermalization and relaxation. We implement the density of states of real materials in our approach [3]. As a result of our simulations, we extract the electron thermalization time and the electron-phonon coupling under non-equilibrium conditions. Examples are given for aluminum, gold an nickel.

[1] Z. Lin et al., Phys. Rev. B 77, 075133 (2008)

[2] B. Rethfeld et al., Phys. Rev. B 65, 214303 (2002)

[3] B. Y. Mueller et al., AIP Conf. Proc. 1461, 609 (2012)