Enhanced magnetoelectric coupling in van der Waals heterostructures

Multiferroic materials, essential for multifunctional devices, face the significant challenge of achieving enhanced magnetoelectric coupling. The advent of two-dimensional (2D) van der Waals (vdW) ferroelectric and magnetic materials presents a unique opportunity to engineer artificial multiferroics via heterostructures. This presentation highlights enhanced magnetoelectric couplings in two insulating vdW heterostructures: CrCl₃/CuCrP₂S₆ and MnBr₂/Nb₃I₈. In the CrCl₃/CuCrP₂S₆ heterostructure, first-principles simulations demonstrate that reversing ferroelectric polarization efficiently switches between interlayer ferromagnetic and antiferromagnetic orders. This effect is attributed to the unique spin local field effect in 2D heterostructures on interlayer exchange interactions. Moving beyond interlayer control, we propose tuning intralayer magnetic orders in frustrated multiferroic heterostructures. In the MnBr₂/Nb₃I₈ heterostructure, there is a competition between frustrated intralayer magnetic orders within the kagome MnBr₂ layer and interlayer magnetic coupling mediated by a spin- local field effect. By manipulating the vertical electric polarization of the Nb₃I₈ layer, we can rebalance these competing interactions, successfully controlling the ground-state intralayer vmagnetic order in MnBr₂. These findings underscore the promising potential of coupling electric polarization with correlated magnetic orders through unique proximity effects in vdW multiferroic heterostructures.