Nanotech 2001 Vol. 2
Nanotech 2001 Vol. 2
Technical Proceedings of the 2001 International Conference on Computational Nanoscience and Nanotechnology

Computational Materials Chapter 6

Ab Initio Molecular Dynamics Study of the Pressure Induced Phase Transformations in Cristobalite

Authors: D.D. Klug, R. Rousseau, K. Uehara, M. Bernasconi and J.S. Tse

Affilation: National Research Council of Canada, Canada

Pages: 129 - 132

Keywords: high-pressure, ab initio calculations, Car-Parrinello, SiO2

The mechanism for the pressure induced transformation of cristobalite to stishovite and post-stishovite phases has been obtained from constant pressure ab initio molecular dynamics simulations. The cristobalite to stishovite transformation is found to be a two step process where SiO4 tetrahedra first rotate followed by a lattice distortion to yield the 6-coordinated stishovite structure. Further compression of stishovite yields the CaCl2 structure and is followed by another 6-coordinated structure with symmetry P21/n (at 11 Mbar) which remains stable to a pressure of about 14 Mbar and then transforms into a 9-coordinated P21/m structure.

ISBN: 0-9708275-3-9
Pages: 218

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