Regensburg 2002 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 46: Poster
DY 46.36: Poster
Donnerstag, 14. März 2002, 15:30–18:00, D
Analysis of the structural properties of a-Si3B3N7 as function of temperature and model parameters — •Alexander Hannemann, J. Christian Schön, and Martin Jansen — Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1,70569 Stuttgart
We study the properties of structural models for amorphous Si3B3N7 at a number of densities. We generate the structural models by the optimization of three types of starting configurations, which exhibit distinct structural features in the next-nearest neighbor topology. The starting configurations were generated from the melt, by sintering of nanocrystals (dcryst=0.5nm) and via a RCP-algorithm. We use different local optimization techniques as well as simulated annealing (with different cooling rates γ) as our optimization tools, while also employing different empirical interaction potentials for the Si3B3N7-system. The structural properties (pair correlation function, mean coordination numbers, etc.) of the structural models for the Si3B3N7-system show that the system contains trigonally-planar BN3 and tetrahedral SiN4 building units, that are mainly linked by one common nitrogen atom. The results are in good agreement with experimental data.
Additionally we have investigated the temperature dependence of these structural properties by means of MC-simulations in the NVT-ensemble. The investigations show that the BN3-units are more strongly bound than the SiN4-units, characterized by their survival times. Furthermore we find that some of the calculated properties depend on the starting configurations.