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K: Fachverband Kurzzeitphysik

K 3: Lasersysteme und deren Anwendungen I

K 3.1: Hauptvortrag

Dienstag, 3. März 2015, 10:15–10:50, HZO 40

Molecular Dynamics Simulation of Laser Ablation with the Two-Temperature Model — •Johannes Roth, Alexander Kiselev, Dennis Rapp, Daniel Förster, Steffen Sonntag, and Hans-Rainer Trebin — Institut für funktionelle Materie und Quantentechnologien (FMQ), Universität Stuttgart

Laser treatment of surfaces has become an indispensable tool for modifying materials. Recently, new applications like micro-steering of satellites have come up.

Supported by the CRC 716, we have developed a molecular dynamics code for large scale simulations of femto-second pulses, taking into account the interaction of the laser with the charge carriers by an enhanced two-temperature model. The modification of the atomistic interaction by the laser irradiation is taken into account by electron-temperature dependent interactions. After introducing the model we will present results on simulations of simple metals, anisotropic alloys, and metallic multi-layer sheets and will discuss the behavior of double pulse sequences which show a decline of effectivity for delay intervals of about 10 ps. Results for covalent materials will also be presented, where there two-temperature model is expanded to describe varying carrier densities. The atomistic interaction is represented by an electron-temperature dependent modified Tersoff potential. The results show that both improvements are essential for good agreement with experimental data. We close by addressing further developments which are necessary to make the simulation code suitable for long laser pulses used in satellite steering.