Character of the incommensurate modulation and the problem of light scattering in quartz near theα↔βtransition

Abstract

It is shown that the observed incommensurate structure near the ␣ ↔ ␤ transition in quartz is a pure transverse acoustic modulation without any optic mode displacements component. Such a long-period acoustic modulation cannot be responsible for the observed light scattering in quartz, contrary to the interpretation by Dolino et al. ͓Phys. Rev. Lett. 94, 155701 ͑2005͔͒.