Enhancing the perpendicular magnetic anisotropy of 1T-FeCl2 monolayer by applying strain: first-principles study

In consideration of importance of enhancing the magnetic anisotropy in ferromagnetic two-dimensional materials for their applications in magnetic data storage and spintronic devices, the structural stability and magnetic stability of FeCl2 monolayer in the 1T phase (1T-FeCl2 monolayer) under different strains and the influence of strain on magnetic stability and perpendicular magnetic anisotropy (PMA) of the 1T-FeCl2 monolayer are investigated using first-principles calculations. It is found that 1T-FeCl2 monolayer under different strains are stable at the room temperature by calculating the phonon dispersion and ab initio molecular dynamics (MD) simulations. Ferromagnetic is always the ground state of the unstrained and strained 1T-FeCl2 monolayer under different strains and the ferromagnetic stability can be enhanced by applying compressive strain. The magnetic anisotropy energy (MAE) of the unstrained 1T-FeCl2 monolayer is positive and the magnetization axis is perpendicular to the 1T-FeCl2 layer. As compressive strain increases, the positive contribution to MAE from SOC interaction between dx2-y2(dxy) and dyz(dxz) states increase, which lead to the MAE of the 1T-FeCl2 monolayer can be enhanced. On the contrary, the tensile strain can make the MAE of the 1T-FeCl2 monolayer weaken. Our results show that strain engineering is an effective approach to enhance PMA of 1T-FeCl2 monolayer.