Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 36: Poster Ib

HL 36.34: Poster

Dienstag, 8. März 2016, 15:00–19:00, Poster A

Phonon dispersion by fitting effective potentials to ab initio data — •Philipp Risius, Marcel Giar, Andreas Rühl, and Christian Heiliger — Institut für theoretische Physik, Justus-Liebig-Universität, 35392 Gießen

Direct ab initio calculation of the forces on atoms is not feasible for materials with small defect concentrations, which have to be represented by large supercells. Effective potentials as used in molecular dynamics simulations could allow this and subsequently enable calculation of phonon dispersion curves.

Defect-free silicon is used as a model system. Effective potentials are generated by matching predicted forces to those calculated with ab initio methods. The resulting potentials are tested for reproduction of small and long-range forces and phonon dispersion curves are calculated from them.

It is found that a modified Embedded Atom Method [1] is best suited for reproducing the reference forces. Here, the phonon dispersion can be reproduced accurately, whereas other potential models perform worse.

[1] Lenosky et al. Model. Simul. Mater. Sci. Eng. 8, 825 (2000).