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K: Fachverband Kurzzeitphysik

K 6: Poster

K 6.8: Poster

Donnerstag, 11. März 2010, 16:30–19:00, Lichthof

Pathways leading to ultrafast melting of silicon — Eeuwe S. Zijlstra, •Tobias Zier, Bernhard Reuter, Bernd Bauerhenne, and Martin E. Garcia — Theoretische Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany

When silicon is excited by a sufficiently intense ultrashort laser pulse, it is known to melt within a picosecond. The femtosecond excitation induces a nonequilibrium state with hot electrons (several 10 000 K) and cold ions (near room temperature). On the basis of density functional theory we study this phenomenon and pay particular attention to the changes of the interionic potential with respect to thermal equilibrium (the ground state). The pathways involved in the ultrafast melting of Si are studied from two complementary points of view, namely, using the phononic degrees of freedom and performing molecular dynamics simulations. Our results allow us to give a microscopic picture of the first stages of the ultrafast melting as well as of the subsequent dynamics.