A novel-type incommensurate phase in quartz: the elongated-triangle phase
Saint-Gregoire P., Luk'yanchuk I., Snoeck E., Roucau ó., Janovec V.
We present the evidence for a thermodynamically stable incommensurate elongated-triangle (.ELT) phase in quartz observed by transmission electron microscopy at structural a — β transition. The phase sequence on cooling is: incommensurate equilateral-triangle (EQT) phase (ferroelectric) incommensurate ELT (ferroelectric and ferroelastic) uniform a phase. The ELT blocks could be responsible for the large light scattering in the vicinity of a — β transition. PACS: 61.16.Bg, 64.70.Rh.