Ab initio simulation of first-order amorphous-to-amorphous phase transition of silicon

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Durandurdu M. , DRABOLD D.

PHYSICAL REVIEW B, cilt.64, 2001 (SCI İndekslerine Giren Dergi) identifier identifier


The pressure-induced phase transition in amorphous silicon (a-Si) is studied using ab initio constant-pressure molecular-dynamic simulations. Crystalline silicon (c-Si) shows a phase transformation from diamond-to-simple hexagonal at. 29.5 GPa, whereas a-Si presents an irreversible sharp transition to an amorphous metallic phase at 16.25 GPa. The transition pressure of a-Si is also calculated from the Gibbs free energy curves and it is found that the transformation takes place at about 9 GPa in good agreement with the experimental result of 10 GPa. We also study the electronic character of the pressure-induced insulator to metal transition.