Domain wall vertices in quartz: Symmetry, classification, and T.E.M. Observation

Abstract

Domain vertices, i.e. junctions of equivalent domain walls that meet along a common line, appear in the 3-q incommensurate phase and in α phase of quartz. We show how their symmetry can be expressed by rod groups and how these groups can be used to classify possible vertices. We list representatives of all non-equivalent vertices and their symmetries and give examples of vertices observed by transmission electron microscopy.