Polarization Textures in Moiré Patterns of van der Waals Homo- and Heterostructures via Sliding Ferroelectrics.

Abstract

Ferroelectricity can emerge in moiré patterns formed by stacking nonferroelectric monolayers, such as graphene and hexagonal boron nitride, in specific configurations. This moiré-induced ferroelectricity not only extends the scope of two-dimensional (2D) ferroelectrics but also deepens our understanding of ferroelectric mechanisms in low-dimensional systems. Here, we present a general framework for analyzing polarization in moiré superlattices by decomposing them into fundamental structural components. In homobilayers, we identify triangular domains with alternating out-of-plane polarization and in-plane textures resembling Néel- and Bloch-type merons, driven by lattice mismatch and twist angle. For heterobilayers, we developed an inverse binomial function that accounts for the spatially varying interlayer biases induced by asymmetries in high-symmetry stacking regions to explore the polarization distribution. This approach can be extended to multilayer heterostructures and moiré systems, providing a unified method for understanding ferroelectric domains and domain walls in 2D materials.