Polarization-driven reversible magnetic anisotropy switching and half-metal to semiconductor transition in intrinsic multiferroic ScCrCO2 monolayer

The precise manipulation of perpendicular magnetic anisotropy is a critical requirement for advancing spintronic device technologies. In this Letter, we propose a design strategy for intrinsic two-dimensional multiferroics rooted in crystal field theory, enabling magnetization reversal through ferroelectric polarization switching. The effectiveness of this strategy is substantiated through the creation of a ScCrCO2 monolayer, where deliberate polarization modulation induces a reversible switching of the easy magnetization axis between in-plane and out-of-plane configurations. This transition stems from dynamic changes in the crystal field splitting of Cr ions. Using atomically resolved and orbital-decomposed magnetic anisotropy energy calculations, we uncover the microscopic origin of polarization-driven magnetic anisotropy in ScCrCO2. Moreover, an accompanying electronic phase transition from a half-metallic to semiconducting state is observed. Our results not only demonstrate a pathway for nonvolatile electrical control of 2D ferromagnets but also advance fundamental understanding and practical applications in magnetoelectric coupling.