Quartz amorphization: A dynamical instability

Abstract

The results of atomistic simulations based on the Born model of solids show that the crystalline-to-amorphous phase transition in α-quartz is the result of a dynamical instability. This work illustrates the potential of atomistic simulation to identify the atomic mechanisms for phase transformations. On applying high pressure to α-quartz, an acoustic vibrational mode became unstable, indicating supercell formation of size 3 × 3 × 1. Further increase in pressure resulted in the collapse of the crystalline structure to an amorphous solid displaying variations in bond length, bond angle and coordination number.