CrI3 monolayer: magnetic and electronic behaviors under biaxial strain and external electric field-a first principle study

We have studied the magnetic and electronic behaviors of CrI3 monolayer under biaxial strain and external electric field using first principle calculation. A magnetic phase transition from ferromagnetic to antiferromagnetic state has been observed under a compressing strain of - 6%. The observed influence of biaxial strain on magnetic anisotropy energy is also surprising. Under zero strain it is as high as 0.74 meV/Cr and increases rapidly with compressing strain reaching a value of 1.53 meV/Cr under a compressing strain of - 6%. Moreover, we observe a switching of magnetic easy axis from off-plane to in-plane direction under a tensile strain of 9%. In addition, the bandgap for spin-up (E-g(up)) from - 10% compressing strain to 10% tensile strain at first increases slowly and exhibits a maximum ((similar to) 0.60 eV) for zero strain. Then it gradually reduces to (similar to) 0.42 eV for 10% tensile strain. However, the bandgap for spindown (E-g(down)) increases monotonically within the entire range and reaches maximum ((similar to) 2.02 eV) for 10% tensile strain. On the other hand, external electric field applied along the off-plane direction (i.e., along c direction) induces significant variations in electronic as well as magnetic (especially MAE) behaviors of CrI3 monolayer.