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Etude théorique à l'échelle nanométrique du carbure de silicium sous
irradiation : modélisation classique et ab initio

Abstract : The behaviour of silicon carbide under irradiation has been studied using classical and ab initio simulations, focusing on the nanoscale elementary processes. First, we have been interested in the calculation of threshold displacement energies, which are difficult to determine both experimentally and theoretically, and also the associated Frenkel pairs. In the framework of this thesis, we have carried out simulations in classical and ab initio molecular dynamics. For the classical approach, two types of potentials have been used : the Tersoff potential, which led to non satisfactory results, and a new one which has been developped during this thesis. This potential allows a better modelling of SiC under irradiation than most of the empirical potentials available for SiC. It is based on the EDIP potential, initially developped to describe defects in silicon, that we have generalized to SiC. For the ab initio approach, the feasibility of the calculations has been validated and average energies of 19 eV for the C and 38 eV for the Si sublattices have been determined, close to the values empirically used in the fusion community. The results obtained with the new potential EDIP are globally in agreement with those values. Finally, the elementary processes involved in the crystal recovery have been studied by calculating the stability of the created Frenkel pairs and determining possible recombination mechanisms with the nudged elastic band method.
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https://tel.archives-ouvertes.fr/tel-00127786
Contributor : Guillaume Lucas <>
Submitted on : Monday, January 29, 2007 - 4:52:11 PM
Last modification on : Thursday, March 28, 2019 - 2:04:04 PM
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Guillaume Lucas. Etude théorique à l'échelle nanométrique du carbure de silicium sous
irradiation : modélisation classique et ab initio. Physique [physics]. Université de Poitiers, 2006. Français. ⟨tel-00127786⟩

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