Comment on the "Origin of the opalescence at the \alpha --\beta transition of quartz: role of the incommensurate phase studied by synchrotron radiation"

TL;DR

This paper critiques a previous interpretation of opalescence in quartz, clarifying that the incommensurate phase involves a pure transverse acoustic modulation, not a soft optic mode, thus challenging earlier explanations of light scattering anomalies.

Contribution

It provides a critical analysis showing that the incommensurate structure in quartz is a pure transverse acoustic modulation, disputing prior claims of a soft optic mode involvement.

Findings

IC structure is a pure transverse acoustic modulation

No soft optic mode component in the IC phase

Challenges previous interpretation of light scattering

Abstract

The interpretation of the origin of the light scattering anomalies near the transition from incommensurate (IC) to the alpha-phase of quartz by Dolino et al. (Phys. Rev. Lett. 94, 155701 (2005)) is commented. It is shown that the observed IC structure is a pure transverse acoustic (TA) modulation without any soft optic mode component. Such a modulation cannot be responsible for the observed light scattering contrary to the interpretation by Dolino et al.