Density Functional Theory Study of Nonvolatile Electrically Controlled Magnetic Anisotropy in Ferromagnetic ScI₂ Monolayer

The regulation of magnetic anisotropy in two-dimensional ferromagnetic materials holds great promise for applications in spintronic devices. Through first-principles calculations, we have constructed a van der Waals multiferroic system composed of a ferromagnetic ScI₂ monolayer (ML) and a ferroelectric In₂Se₃ ML, demonstrating the nonvolatile electrical control of magnetic anisotropy. By manipulating the polarization direction of the In₂Se₃ ML, we can transform a ScI₂ ML with a two-dimensional XY ferromagnetism into an Ising ferromagnet. Our research reveals that the coupling between the unoccupied (u) and occupied (o) states of the I'p and Sc'd orbitals leads to changes in the magnetic anisotropy energy. Moreover, flipping the polarization direction of the In₂Se₃ ML can convert the heterostructure from a semiconductor to a metal, enabling us to propose a novel storage device in which data can be written while retaining the advantages of traditional ferroelectric memory. Importantly, the ferroelectric control of the electronic properties of the ScI₂ ML allows for nondestructive data readout. These discoveries establish another insight for spin manipulation in spintronics.