Strong magnetic proximity effect in van der Waals heterostructures driven by direct hybridization

We propose another class of magnetic proximity effects based on the spin-dependent hybridization between the electronic states at the Fermi energy in a nonmagnetic conductor and the narrow spin-split bands of a ferromagnetic insulator. Unlike conventional exchange proximity, we show this hybridization proximity effect has a very strong influence on the nonmagnetic layer and can be further modulated by application of an electric field. We use density functional theory calculations to illustrate this effect in graphene placed next to a monolayer of CrI3, a ferromagnetic insulator. We find strong hybridization of the graphene bands with the narrow conduction band of CrI3 in one spin channel only. We show that our results are robust with respect to lattice mismatch and twist angle variations. Furthermore, we show that an out-of-plane electric field can be used to modulate the hybridization strength, paving the way for applications.