Spin Transport Properties of MnBi₂Te₄-Based Magnetic Tunnel Junctions

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 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, Cu/MnBi2Te4/MnBi2Te4/Cu and Cu/MnBi2Te4/h-BN/n·MnBi2Te4/Cu(n = 1, 2, 3). We find that the maximum TMR of Cu/MnBi2Te4/h-BN/3·MnBi2Te4/Cu MTJ can reach 162.6%, exceeding the system with only a single layer MnBi2Te4. More interestingly, our results indicate that Cu/MnBi2Te4/h-BN/n· MnBi2Te4/Cu (n = 2, 3) MTJs can realize the switching function, while Cu/MnBi2Te4/h-BN/3· MnBi2Te4/Cu MTJ exhibits the negative differential resistance. The Cu/MnBi2Te4/h-BN/3·MnBi2Te4/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 MnBi2Te4-based van der Waals magnetic tunneling junctions.