Simulation study of polymorphism and diffusion anomaly for SiO2 and GeO2 liquid
Department of Computational Physics, Hanoi University of Technology, Hanoi, Vietnam
Corresponding author: a email@example.com
Revised: 9 June 2009
Published online: 11 August 2009
We report molecular dynamic (MD) simulations of a silica and germania liquid. We show for the first time that the liquid models constructed of the BKS and Ocffner-Elliott potential are composed of D4, D5 and D6 domains. These domains of different liquids (identical chemical composition but different density) are structurally identical. The liquid densification occurs gradually with variation in the volume of the D4, D5 and D6 domains. The void radius distributions (VRD) have been computed and they are well fitted to a Gaussian form. Both the average void radii and width of the VRD decrease with pressure. The diffusivity of Si/Ge or O depends linearly on the fraction of TOx (x = 4, 5 and 6; T is Ge or Si). The diffusion anomaly results from the very high mobility of silicon in the D5 domain compared to domains D4 and D6.
PACS: 61.43.Fs – Glasses / 61.20.Lc – Time-dependent properties; relaxation
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009