Theory of slidetronics in ferroelectric van der Waals layers

Abstract

Ferroelectricity can emerge in vertically stacked two-dimensional materials even when their constituent monolayers are nonferroelectric. In these sliding ferroelectrics, polarization switching is driven by small lateral displacements between layers. Here, we develop a comprehensive materials design framework for slidetronics founded on a symmetry principle: any sliding-induced polarization change from a state P to P' can be equivalently described by applying an appropriate point-group operator, or "generator" G, to the entire system, such that P' = GP. This generator-based framework classifies all possible sliding-induced transformations, establishes the necessary symmetry conditions for switchable polarization components, and provides design strategies for realizing targeted switching behaviors. A central result is that complete polarization inversion is symmetry forbidden in bilayers but becomes possible in multilayers. First-principles calculations confirm these predictions, revealing novel phenomena including dipole-locked ferroelectricity in cellulose bilayers, in-plane switching in As2S3-based systems, and full polarization reversal in a PdSe2 trilayer.