Enhanced magnetoelectric coupling in two-dimensional hybrid multiferroic heterostructures

Magnetoelectric coupling in insulating multiferroic materials holds significant value in both fundamental research and multifunctional device applications. However, material realization remains highly challenging. We predict enhanced magnetoelectric coupling in a multiferroic van der Waals heterostructure composed of CrCl₃ and CuCrP₂S₆. In this heterostructure, the intralayer orders exhibit characteristics of a type-I multiferroic, while the interlayer orders are more akin to a type-II multiferroic, forming a hybrid-type multiferroic. Notably, the interlayer magnetic configuration can be switched upon electric polarization reversal, while maintaining the insulating property without any nontrivial phase transitions. Our analysis reveals substantial band alignment variations and a strongly asymmetric spin local-field effect under electric polarization. Particularly, these two factors synergistically work together in deciding the interlayer exchange interactions, achieving enhanced magnetoelectric coupling. Finally, we demonstrate that this magnetoelectric effect is robust in multi-layer structures and can even control the Néel vector, which is known difficult to be manipulated. This study indicates promising prospects to search for enhanced magnetoelectric couplings in hybrid multiferroic heterostructures.