2D Covalent Moiré Superlattice from Fluorinating Twisted Bilayer Graphene

Abstract

Moiré materials exhibit diverse quantum properties such as superconductivity and correlated topological phases, making them ideal for studying strongly correlated systems. While moiré materials are typically formed by stacking 2D materials with interlayer interaction dominated by weak van der Waals (vdW) forces, constructing moiré covalent superlattices by fluorinating twisted bilayer graphene becomes possible. With first principles calculations, it is demonstrated that fluorination of twisted bilayer graphene (TBG) can induce covalent bonds between adjacent layers, transforming the vdW‐dominated interactions. This results in enhanced modulation of the electronic structure, with abundant flat bands across the spectrum. The findings suggest that covalent moiré superlattices offer new platforms for exploring correlated quantum phenomena and moiré covalent chemistry.