Intriguing Magnetoelectric Effect in Two-dimensional Ferromagnetic/Perovskite Oxide Ferroelectric Heterostructure

Abstract: Two-dimensional (2D) magnets have broad application prospects in the spintronics, but how to effectively control them with a small electric field is still an issue. Here we propose that 2D magnets can be efficiently controlled in a multiferroic heterostructure composed of 2D magnetic material and perovskite oxide ferroelectric (POF) whose dielectric polarization is easily flipped under a small electric field. We illustrate the feasibility of such strategy in the bilayer CrI3/BiFeO3(001) heterostructure by using the first-principles calculations. Different from the traditional POF multiferroic heterostructures which have strong interface interactions, we find that the interface interaction between CrI3 and BiFeO3(001) is van der Waals type. Whereas, the heterostructure has particular strong magnetoelectric coupling where the bilayer CrI3 can be efficiently switched between ferromagnetic and antiferromagnetic types by the polarized states of BiFeO3(001). We also discover the competing effect between electron doping and the additional electric field on the interlayer exchange coupling interaction of CrI3, which is responsible to the magnetic phase transition. Our results provide a new avenue for the tuning of 2D magnets with a small electric field.