Nonvolatile ferromagnetism in bilayer CrI3 induced by a heterointerface

The realization of a ferromagnetism in bilayer $\mathrm{Cr}{\mathrm{I}}₃$, an antiferromagnetic semiconductor in its ground state, recently has gained extensive attention for both fundamental and applied research. Despite much effort devoted to this topic, so far its nonvolatile ferromagnetism has not been achieved. Here, we report the realization of nonvolatile ferromagnetism in bilayer $\mathrm{Cr}{\mathrm{I}}₃$. Using first-principles calculations, we reveal that when interfacing with monolayer MoSeTe, the magnetic ground state of bilayer $\mathrm{Cr}{\mathrm{I}}₃$ transforms from antiferromagnetism to ferromagnetism. Also, depending on the interfaced surface of monolayer MoSeTe, bilayer $\mathrm{Cr}{\mathrm{I}}₃$ can be ferromagnetic semiconducting or half-metallic. We unveil that the obtained ferromagnetic transformation in bilayer $\mathrm{Cr}{\mathrm{I}}₃$ can be attributed to the competition between orbital-dependent interlayer antiferromagnetic super-super-exchange and ferromagnetic super-super-exchange. Our work not only provides a promising way to engineer nonvolatile ferromagnetism in bilayer $\mathrm{Cr}{\mathrm{I}}₃$, but also renders bilayer $\mathrm{Cr}{\mathrm{I}}₃$ an appealing platform for developing two-dimensional spintronics.