New Incommensurate Elongated-Triangle Phase in Quartz

TL;DR

This paper reports the discovery of a new incommensurate elongated-triangle phase in quartz, observed via electron microscopy, revealing a complex phase sequence with potential implications for light scattering near the transition.

Contribution

First evidence of a thermodynamically stable incommensurate elongated-triangle phase in quartz, expanding understanding of its phase transition sequence.

Findings

Identification of the $ELT$ phase in quartz

Observation of the phase sequence during cooling

Potential link between $ELT$ blocks and light scattering

Abstract

We present for the first time the evidence for a thermodynamically stable incommensurate elongated-triangle ($ELT$) phase in quartz observed by transmission electron microscopy at structural $\alpha -\beta $ transition. The phase sequence on cooling is: uniform $\beta $ phase - stripe incommensurate phase (ferroelastic) - incommensurate equilateral-triangle ($EQT$) phase (ferroelectric) - incommensurate $ELT$ (ferroelectric and ferroelastic) - uniform $\alpha $ phase. The $ELT$ blocks could be responsible for the large light scattering in the vicinity of $\alpha-\beta$ transition.