We have synthesized micrometer-scale polyhedral ring crystals of TaS3 by the chemical vapor transportation method. The polyhedral ring crystals are closed-loop crystals with several vertices. We investigated the crystallinity and flatness of the facets by the electron backscatter diffraction technique and found that the orientation of the crystal axis changed abruptly at several points. Observing the size of the crystals, we found a new phase of topological crystals and propose a phase diagram of ring-polyhedral crystals in terms of radius and thickness. We also propose a mechanism of polygonization in which the vertices of the polyhedral crystals are formed from concentrated dislocations as a result of distancedependent interactions between them.
Reprinted (adapted) with permission from Crystal Growth and Design. Copyright 2011 American Chemical Society.