Spin Transport Properties of MnBi<sub>2</sub>Te<sub>4</sub>-Based Magnetic Tunnel Junctions
Xinlong Dong, Xin Jia, Zhi Yan, Xuemin Shen, Zeyu Li, Zhenhua Qiao, Xiaohong Xu
Abstract
The van der Waals heterojunctions, stacking of different two-dimensional materials, have opened unprecedented opportunities to explore new physics and device concepts. Here, combining the density functional theory with non-equilibrium Green's function technique, we systematically investigate the spin-polarized transport properties of van der Waals magnetic tunnel junctions (MTJs), Cu/MnBi 2 Te 4 /MnBi 2 Te 4 /Cu and Cu/MnBi 2 Te 4 /h-BN/ n ⋅MnBi 2 Te 4 /Cu ( n = 1, 2, 3). It is found that the maximum tunnel magnetoresistance of Cu/MnBi 2 Te 4 /h-BN/3⋅MnBi 2 Te 4 /Cu MTJs can reach 162.6%, exceeding the system with only a single layer MnBi 2 Te 4 . More interestingly, our results indicate that Cu/MnBi 2 Te 4 /h-BN/ n ⋅MnBi 2 Te 4 /Cu ( n = 2, 3) MTJs can realize the switching function, while Cu/MnBi 2 Te 4 /h-BN/3⋅MnBi 2 Te 4 /Cu MTJs exhibit the negative differential resistance. The Cu/MnBi 2 Te 4 /h-BN/3⋅MnBi 2 Te 4 /Cu in the parallel state shows a spin injection efficiency of more than 83.3%. Our theoretical findings of the transport properties will shed light on the possible experimental studies of MnBi 2 Te 4 -based van der Waals magnetic tunneling junctions.