Nonvolatile Electrical Control and Heterointerface-Induced Half-Metallicity of 2D Ferromagnets

Electrical control of atom-thick van der Waals (vdW) ferromagnets is a key toward future magnetoelectric nanodevices; however, state-of-the-art control approaches are volatile. In this work, introducing ferroelectric switching as an aided layer is demonstrated to be an effective approach toward achieving nonvolatile electrical control of 2D ferromagnets. For example, when a ferromagnetic monolayer CrI3 and ferroelectric MXene Sc2CO2 come together into multiferroic heterostructures, CrI3 is controlled by polarized states P up arrow and P down arrow of Sc2CO2. P up arrow Sc2CO2 does not change the semiconducting nature of CrI3, but surprisingly P down arrow Sc2CO2 makes CrI3 half-metallic. Nonvolatility of the electrical switching between two oppositely ferroelectric polarized states, therefore, indirectly enables nonvolatile electrical control of CrI3 between ferromagnetic semiconductor and half-metal. The heterointerface-induced half-metallicity in CrI3 is intrinsic without resorting to any chemical functionalization or external physical modification, which is rather beneficial to the practical application. This work paves the way for nonvolatile electrical control of 2D vdW ferromagnets and applications of CrI3 in half-metal-based nanospintronics.