Reversible switching of half-metallicity and magnetic order in 2D FeI2/Al2Te3 van der Waals multiferroics tailored by ferroelectric polarization.

Non-volatile, all-electric spin manipulation stands as a pivotal objective in the development of next-generation, low-power, and highly compact spintronic devices. A promising strategy to realize such functionality lies in harnessing magnetoelectric coupling within van der Waals (vdW) multiferroic heterostructures. Motivated by this potential, we conduct a systematic first-principles density functional theory investigation of a two-dimensional vdW multiferroic heterostructure, formed by stacking a ferromagnetic metallic FeI2 monolayer onto a ferroelectric semiconducting Al2Te3 monolayer. Our calculations reveal a pronounced magnetoelectric coupling effect near room temperature. Crucially, reversing the ferroelectric polarization of the Al2Te3 layer not only triggers a reversible transition in the electronic state of the FeI2 layer from semiconducting to half-metallic but also allows precise control over its magnetic anisotropy energy (MAE). Furthermore, this electric field-driven polarization switching induces a magnetic phase transition from antiferromagnetism (AFM) to ferromagnetism (FM) in FeI2, while the semiconducting character of Al2Te3 remains intact. These findings establish the FeI2/Al2Te3 heterostructure as a highly promising platform for non-volatile all-electric spin control and provide a fundamental theoretical basis for designing high-performance, multiferroic-based memory devices.