Synthesizing Two-Dimensional Chiral Cobalt Telluride through a Predesigned Buffer Layer.

Abstract

Two-dimensional (2D) chiral systems are highly attractive for applications in enantioselective catalysis, spin-polarized optoelectronics, and quantum information technologies, yet they are challenging in controllable and scalable synthesis. Here, we demonstrate the epitaxial growth of 2D chiral cobalt telluride (CoTe₂) on an achiral Au(111) substrate, using molecular beam epitaxy corroborated by scanning tunneling microscopy and density functional theory calculations. Initial Te deposition results in the formation of an Au₂Te buffer layer, which guides the generation of CoTe₂ linear chain intermediates upon Co addition. Subsequent Te exposure transforms these chains into a defective 1T-CoTe₂ monolayer, where Te vacancies arrange into a chiral pinwheel superlattice. Further Te deposition heals the defects and yields a complete 1T-CoTe₂ monolayer exhibiting spiral patterns with chirality. This work reveals a strain-mediated mechanism governing chiral pattern formation and establishes a scalable pathway for creating chiral 2D materials with tailored architectures.