Oxygen neutral defects in silica: Origin of the distribution of the formation energiesL. Martin-Samos1, Y. Limoge1, N. Richard2, J. P. Crocombette1, G. Roma1, E. Anglada3 and E. Artacho4
1 Service de Recherche en Métallurgie Physique, CEA-Saclay 91191 Gif-sur-Yvette, France
2 CEA-DIF - Bruyère-le-Châtel, France
3 Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid Madrid, Spain
4 Department of Earth Sciences, University of Cambridge - Cambridge, UK
(Received 14 October 2003; accepted in final form 26 March 2004)
We present a numerical study of the neutral oxygen defects in silica. This work was performed using two complementary approaches: molecular dynamics using an empirical potential and ab initio calculations. We show that the formation energy fluctuates from point to point. The dispersion is due to the fluctuations of the local stress before defect creation. Using lattice statics, we establish the relation between the local-stress fluctuations inherent in the glassy state and the formation energies.
61.72.Bb - Theories and models of crystal defects.
61.43.Fs - Glasses.
© EDP Sciences 2004