Dresden 2009 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 11: Photonic Dielectrics II

DF 11.6: Vortrag

Mittwoch, 25. März 2009, 16:30–16:50, WIL A317

Ab-initio determination of the pathways of laser-induced non-thermal melting of InSb — •Jessica Walkenhorst, Eeuwe S. Zijlstra, and Martin E. Garcia — Theoretische Physik, Fachbereich Naturwissenschaften, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany

We performe ab-initio calculations and dynamical simulations to explain the pathways of ultrafast non-thermal melting in InSb during the first 100’s of femtoseconds after intense femtosecond laser excitation. We compute the potential energy surface of femtosecond-laser-excited InSb along the directions in which the crystal becomes soft. Using dynamical simulations the time dependence of the atomic coordinates is obtained. We find that at high excitation densities the anharmonicity of the potential energy surface becomes significant after ≈ 100 fs. On the basis of our results we explain recent timeresolved x-ray diffraction experiments as reported by Lindenberg et al. [A. M. Lindenberg et al., Science 308, 392 (2005)]. Furthermore we compute the atomic density evolution in time after the laser excitation.