Polyhedral Topological Crystals

Abstract

We synthesized micrometer-scale polyhedral ring-crystals of TaS 3 , 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 pattern technique, and revealed that the orientation of crystal axis changes abruptly at several points. Observing the size of the crystals, we found a new phase of topological crystals, and proposed a phase diagram of ring-polyhedral crystals in terms of radius and thickness.We proposed the mechanism of polygonization in which the vertices of the polyhedral crystals are formed of concentrated dislocations caused by the distance-dependent interaction between them.

Salt‐Assisted Vapor–Liquid–Solid Growth of 1D van der Waals Materials

“…Some curl up toward the free-end tip, resembling a spiral structure (Figure 1f). Similar "topological crystals" [43,44] have been observed in bulk NbSe 3 and TaSe 3 synthesized by chemical vapor transport. [43] Measurements of the cross-section areas, lengths, and diameters of different NbS 3 morphologies can be found in Figure S6, Supporting Information.…”

Monoclinic structures of niobium trisulfide

“…Such "topological crystals," previously observed for TaS 3 , NbSe 3 , and TaSe 3 , apparently form when droplets of molten elemental chalcogen template crystal growth. [42][43][44][45][46] Indeed, Enyashin and Ivanovskiȋ have provided a theoretical basis indicating that NbS 3 ring structures are energetically favorable. 47 Continuing work will be required to understand the formation mechanism of such morphologies in the NbS 3 system and characterize the distortions that accompany crystal bending.…”

Ring formation of transition metal trichalcogenide TaSe3 using vapor liquid process

“…This also implies that the distribution of dislocations/disclinations in a topological crystal must be smooth (Tsuneta et al, 2010;Matsuura et al, 2011). When a topological crystal needs to be bent, geometrical frustration is relieved by the inclusion of edge dislocations, while other types of dislocations, such as screw and mixed dislocations, are not necessary to consider (Tsubota et al, 2011).…”