Strain modulation of magnetic properties of monolayer and bilayer FePS3 antiferromagnet

Different from the extensive progresses on two-dimensional (2D) intrinsic ferromagnets, modulation of magnetism in a 2D antiferromagnet is less explored. In this work, we investigate the impact of strain on magnetism of monolayer and bilayer FePS₃ antiferromagnet using first-principles calculations. Our results show that zigzag antiferromagnetic (AFM) state is the ground state of monolayer FePS₃ and the AFM order is very robust to strain. The in-plane and out-of-plane magnetic anisotropy energies (MAEs) of monolayer FePS₃ are 0.31 and 1.41 meV/cell, and MAE is mainly provided by Fe atoms. Interestingly, compressive strain can enhance monotonically MAE of monolayer FePS₃ while the MAE experiences a fall-rise-fall process under tensile strain. In addition, interlayer coupling of bilayer FePS₃ is quite sensitive to strain and undergoes an AFM-FM-AFM transition under both tensile and compressive strain. The out-of-plane direction is also energetically favorable for unstrained bilayer FePS₃ with in-plane and out-of-plane MAEs of 0.58 and 1.54 meV/cell, respectively. with the decrease of strain from 8% to −8%, the MAE of bilayer FePS₃ can be enhanced except a small decrease at the strain of −8%. These findings are essential for applications of FePS₃ based low-dimensional antiferromagnetic spintronic devices.