Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 77: Focus Session: Structural Dynamics in Nanoscale Materials Probed by Ultrashort Electron Pulses

O 77.8: Talk

Thursday, March 19, 2015, 13:00–13:15, MA 005

Femtosecond-laser-excited silicon surfaces — •Tobias Zier, Eeuwe S. Zijlstra, and Martin E. Garcia — University of Kassel, Germany

A femtosecond-laser irradiation of crystalline silicon leads to interesting ultrafast phenomena, like thermal phonon squeezing [1], fractional diffusion and ultrafast melting [2], because of the highly non-equilibrium conditions created by the excitation. In particular, the energy is deposited mostly in the electronic system, which results in a very high electronic temperature (of the order of 10 000 K), and gives rise to an extreme change in the potential energy surface for the ions and therefore in the bonding character of the crystal. With our in-house code CHIVES we perform MD-simulations of femtosecond-laser excited solids which allows us to analyse the microscopic atomic motions near the surface. We check the possibility of femtosecond-laser-induced structural phenomena at the surface, the existence of coherent vibrational surface states and the influence on the above mentioned phenomena.

[1] E. S. Zijlstra, A. Kalitsov, T. Zier, M. E. Garcia, Phys. Rev. X 3,011005 (2013)

[2] E. S. Zijlstra, A. Kalitsov, T. Zier, M. E. Garcia, Adv. Mater. 25, 5605 (2013)