Electrical control of magnetism in 2D CrI₃

Controlling magnetism by purely electrical means is a key challenge to better information technology. The recent discovery of two-dimensional van der Waals magnets has opened a new door for electrical control of magnetism at the nanometer scale through the van der Waals heterostructure device platform. We demonstrate control of magnetism in monolayer and bilayer CrI₃ by application of pure electric field or electrostatic doping. In bilayer CrI_3, we observe a large linear magnetoelectric effect, whose sign depends on the interlayer antiferromagnetic order. In monolayer CrI₃, doping significantly modifies the saturation magnetization, coercive force and Curie temperature, showing strengthened (weakened) magnetic order with hole (electron) doping. Remarkably, in bilayer CrI₃ doping drastically changes the interlayer magnetic order, causing a transition from an antiferromagnetic ground state in the pristine form to a ferromagnetic ground state. These results reveal the strong electric field and doping-dependent interlayer exchange coupling, which enables us to achieve the robust and reversible switching of magnetization in bilayer CrI₃ by small gate voltages.