Theoretical Investigation of Topological Magnetic Textures in Sliding Ferroelectric CrX3 (X = Cl, Br, I) Moire Superlattices: A Multiferroic Material with Unique Magnetoelectric Coupling for Information Storage Applications

Two-dimensional (2D) van der Waals (vdW) materials offer unprecedented possibilities for manipulating electrical and magnetic properties through layer twisting or sliding. In this study, we investigate the stack engineering of two magnetic monolayers, CrX3 (X = Cl, Br, I), by combining first-principles calculations and atomic spin dynamics simulations. The interlayer sliding of CrX3 bilayers disrupts space inversion symmetry, resulting in the emergence of ferroelectric polarization characterized by a low energy potential barrier and polarization reversal. Notably, as the halogen atoms change from Cl to I, the interlayer exchange interaction gradually intensifies, leading to a significant enhancement in both magnetic stability and ferroelectric polarization. Moreover, when a moire superlattice is formed through small-angle twisting, the electrostatic moire potential and magnetic exchange interaction coupling through layer stacking lead to the formation of staggered polarization domains and four distinct types of topological magnetic states, which starkly contrast with the nontwisted bilayer configuration. This work provides a pioneering example of designing sliding ferroelectricity in 2D vdW magnetic bilayers, showcasing the potential of nanoscale layered multiferroic materials constructed by twisted stacking engineering for application in novel information memory devices.