Bandgap opening and magnetic anisotropy switching by uniaxial strain in graphene/CrI3 heterojunction

Two-dimensional van der Waals (vdW) heterojunctions are significant building blocks for optoelectronic and spintronic devices. By first-principle calculations, we study the influence of uniaxial strain on the bandgap and magnetism of graphene/CrI3 heterojunction. The results show that the bandgap size of graphene in heterojunction can reach up to 0.5 eV, and it increases more obvious at the compressive strain relative to the isolated graphene resulting from stronger interlayer proximity exchange. Interestingly, we find that the proximity exchange can induce charge accumulation like a dumbbell between the nearest neighbor C-C atoms along the armchair direction. Unexpectedly, the uniaxial strain induces the magnetic anisotropy switching from out-of-plane to in-plane, while this change does not occur in isolated CrI3. Our findings can provide theoretical guidance for the application of graphene/CrI3 materials.