Energy level-dependent tunneling magnetoresistance based on two-dimensional noncollinear antiferromagnet

Abstract Noncollinear antiferromagnet (NCAFM) with spin polarization in momentum space stands out due to its potential application in AFM spintronics. However, low symmetry and Dzyaloshinskii–Moriya interaction make noncollinear magnetic moment arrangements difficult for two-dimensional (2D) AFM. Herein, we discovered that in the supercell of NiGa 2 S 4 , the magnetic moments provided by three Ni atoms in its ground state are arranged in a noncollinear pattern. Analysis of the electronic structure reveals that it exhibits a remarkable momentum-dependent spin polarization. Moreover, changes in the orientation of the Néel vector can lead to alterations in the spin distribution similar to those in ferromagnets. Enhanced interlayer coupling significantly boosts spin polarization in momentum space, thereby substantially increasing the tunneling magnetoresistance (TMR) of NiGa 2 S 4 -based magnetic tunnel junction (MTJ) (The maximum TMR reaches as high as 4232% at the trilayer). Meanwhile, MTJ exhibits a stronger TMR near the Fermi level. This leads to the MTJ featuring a TMR controllable by a small bias voltage or electron and hole doping. Our work is expected to provide a solution for designing 2D NCAFM MTJ with easily controllable and detectable Néel vectors.