Unveiling Trigonal Anti-Prismatic Structure and Stacking Sequences in InTe

Polymorphic phases of 2D van der Waals layered materials attract significant research interest due to their diverse properties. There is a growing need to synthesize novel polymorphs and explore their atomic-level structures. In this study, molecular beam epitaxy (MBE) is used to grow indium telluride, a III-VI metal chalcogenide with promising applications, on graphene substrates. Atomic resolution scanning transmission electron microscopy reveals that the grown layers exhibit both the well-known trigonal prismatic structure and a less common trigonal anti-prismatic structure, leading to novel stacking sequences. The stability of this unconventional structure is further analyzed using density functional theory calculations, and its potential topological properties are investigated. These findings indicate that III-VI metal chalcogenides are capable of forming polymorphs with diverse symmetries and topological phases beyond their conventional structures. Furthermore, MBE proves to be a viable method for synthesizing such polymorph.