Stability limits and transformation pathways of alpha-quartz under high pressure

Article

关键词: INDUCED AMORPHIZATION;    PHASE;    SILICA;    TRANSITION;    DENSITY;    SIO2;    POLYMORPHISM;    INSTABILITY;   

DOI  :  10.1103/PhysRevB.95.104112

来源: SCIE

【 摘 要 】

Ubiquitous on Earth, alpha-quartz plays an important role in modern science and technology. However, despite extensive research in the past, themechanism of the polymorphic transitions of alpha-quartz at high pressures remains poorly understood. Here, combining in situ single-crystal x-ray diffraction experiment and advanced ab initio modeling, we report two stability limits and competing transition pathways of alpha-quartz under high pressure. Under near-equilibrium compression conditions at room temperature, alpha-quartz transits to a new P2/c silica phase via a structural intermediate. If the thermally activated transition is kinetically suppressed, the ultimate stability of alpha-quartz is controlled by its phonon instability and alpha-quartz collapses into a different crystalline phase. Our studies reveal that pressure-induced solid-state transformation of alpha-quartz undergoes a succession of structural stability limits, due to thermodynamic and mechanical catastrophes, and exhibits a hierarchy of transition pathways contingent upon kinetic conditions.

【 授权许可】

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