Dresden 2009 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
MM: Fachverband Metall- und Materialphysik
MM 34: Liquid and Amorphous Metals I
MM 34.6: Talk
Wednesday, March 25, 2009, 16:00–16:15, IFW D
Laser induced non-thermal melting of germanium — •Momar S. Diakhate1, Harald O. Jeschke2, and Martin E. Garcia1 — 1Theoretische Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany. — 2Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt, Germany.
We study the ultrafast non-thermal melting in bulk germanium. By performing molecular dynamics simulations on time-dependent potential energy surfaces and also static frozen phonon calculations, both based on a non orthogonal tight-binding Hamiltonian, we describe the nonequilibrium melting process occurring in bulk germanium under ultrafast laser pulse excitation. The laser parameters are explicitly taken into account. We show that, upon laser heating, all transverse acoustic phonon modes becomes strongly affected and even destabilized, which drives the melting process. We calculate the time-dependence of the structural properties, in particular the structure factor, and predict the time-dependence of different Bragg-peaks. Our simulations yield nonthermal melting of Ge in less than 1ps after laser excitation.