Stacking engineering in two-dimensional multiferroic CuInP₂S₆/CrI₃ heterostructures

Stacking engineering offers a powerful technique to achieve the desired properties of two-dimensional (2D) van der Waals materials <i>via</i> interlayer coupling, thereby enabling multifunctional applications. In this study, we systemically investigated the electronic and magnetic properties of multiferroic heterostructures consisting of a ferroelectric (FE) monolayer of CuInP₂S₆ and a ferromagnetic/antiferromagnetic (FM/AFM) monolayer/bilayer of CrI₃. Our first-principles calculations unveiled that the reversal of the polarization direction in CuInP₂S₆ can effectively modulate the band gap, band alignment, band type and magnetic ordering of CrI₃. The formation of type II band alignment in the CuInP₂S₆-(P↓)/monolayer-CrI₃ heterojunction results in strong photocatalytic activity under visible light. Additionally, the FE polarization-induced magnetic ground state transition from the AFM state to the FM state and enhancement of the magnetic transition temperature are identified in the CuInP₂S₆/bilayer-CrI₃ heterostructure. Our work not only introduces promising candidates for the development of new electric field-modulated optoelectronic and spintronic devices, but also provides a manufacturable platform for in-depth exploration of magnetoelectric coupling in multiferroic heterostructures.