Regensburg 2019 – wissenschaftliches Programm
O 63.7: Poster
Mittwoch, 3. April 2019, 17:45–20:00, Poster B1
Surface motion of femtosecond-laser excited silicon films — Tobias Zier1, •Marie Kempkes1, Sabrina Schuster1, Lukas Nöding1, J. Gaudin2, P. Martinez2, V. Blanchet2, D. Descamps2, S. Petit2, A. Lévy3, and Martin E. Garcia1 — 1Theoretische Physik, Universität Kassel, Kassel, Germany — 2CEntre Lasers Intenses et Applications, Talence, France — 3Institut des Nanosciences de Paris, France
Surfaces are active regions that exhibit various effects, like, structural reconstructions, already in the thermodynamic ground state. The underlying reason for most of these effects is the broken symmetry at the surface, which modifies the interatomic bonding of surface atoms. After an intense femtosecond-laser pulse the interatomic bonding characteristic of the whole irradiated area is changed due to the induced non-equilibrium conditions, which are characterized by an extremely hot electronic system and nearly unaffected room temperature atoms. Therefore, the bonding of surface atoms is modified twice after a femtosecond-laser excitation, which makes a prediction for the surface behavior non-trivial. We examined the surface response to a femtosecond-laser irradiation by performing ab initio MD simulations of a thin silicon film using our code CHIVES (Code for Highly excIted Valence Electron Systems). Our results can directly be compared to recent time-resolved optical measurements, thus allowing us to unravel the surface response to femtosecond-laser excitation on an atomistic level.