Pressure induced ferromagnetism and magnetic anisotropy in bilayer CrI3*

Two diemnsional CrI3 system has attracted extensive research interest because it is an intrinsic 2D ferromagnetic material with a band gap. It has been found that the monolayer of CrI3 possesses an intrinsic ferromagnetic ordering with a finite band gap of 1.1 eV and it has also a strong perpendicular magnetocrystalline anisotropy. Besides, it has been experimentally reported that the anti-ferromagnetic interlayer coupling in bilayer CrI3 structure could be change by external charge doping. Nonetheless, despite a few experimental works on CrI3 system, it is rare to find the theoretical studies on bilayer CrI3. We investigated the magnetic properties of bilayer CrI3 using density functional approach. We found that the pristine bilayer CrI3 had an anti-ferromagnetic ground state. Interestingly, we obtained that the external pressure could induce a transition from anti-ferromagnetic to ferromagnetic state in bilayer CrI3 and the perpendicular magnetic anisotropy was still preserved even under the external pressure.