Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 83: Poster Focus Session: Structural Dynamics in Nanoscale Materials, Probed by Ultrafast Electron Pulses

O 83.5: Poster

Mittwoch, 14. März 2018, 18:15–20:30, Poster A

Nonequilibrium dynamics of laser excited SiC: Description of Laser excited SiC with the help of classical physics — •Malwin Xibraku, Bernd Bauerhenne, Sergej Krylow, and Martin E. Garcia — University of Kassel, Theoretical Physics, Heinrich-Plett-Straße 40, 34132 Kassel, Germany

Silicon carbide (SiC) nanocrystals are of great interest in medicine, because of their pleasant properties, such as biocompability, high chemical and thermal stability. These nanocrystals can be very well generated using ultrashort laser pulses. Density Functional theory (DFT) has proven to be a appropriate tool to describe the influence of ultrashort laser pulses on solids due to the accurate quantum mechanical treatment of electrons. Due to the fact that 48 million particles are already contained in a cube SiC of side length 100 nm, such a system cannot be computed with DFT. Therefore, the aim of this work is to describe the forces between the atoms in the SiC cube by an effective potential in the context of classical physics. The classical potential should include the effect of the quantum properties of electrons as accurately as possible. Recently, we found such a potential for silicon (Si) and carbon (C). Therefore, the main goal of this work is to generalize the shape of those potentials to solids consisting of two types of atoms. We propose a general shape of a potential for laser excited binary solids and obtain the coefficients by fitting to data obtained from ab initio simulations on small supercells of SiC. We discuss the quality of the obtained potential by comparing MD simulations performed both with the potential and ab-initio.