Effects of temperature and tilt angle on the grain boundary structure in silicon oxide: Molecular dynamics study

Abstract

Molecular Dynamic (MD) simulations on a crystalline and amorphous silicon oxide were performed by using modified-Born-Mayer-Huggins (modified-BMH) potential. Comparison of the lattice parameters and analyses of the RDF for five different bulk phases of silicon oxide showed that the modified-BMH potential was properly able to describe crystalline phases, as well as the amorphous phase. When a polycrystalline model system that was composed of two beta-cristobalite grains with a tilt grain boundary was annealed, an amorphous-like grain boundary region formed. The thickness of the grain boundary region was practically identical, regardless of the annealing temperature within the MD calculation time, which showed a very early stage of grain boundary amorphization. The atomic distribution in the grain boundary region became more uniform as the annealing temperature increased due to the faster relaxation. On the other hand, the atomic configuration and the thickness of the grain boundary region hardly depended on the grain boundary tilt angle.