Giant tunneling magnetoresistance in CrBr3-based van der Waals magnetic tunnel junctions

The recent discovery of two-dimensional (2D) layered intrinsic ferromagnets provides a desirable platform for overcoming technical challenges posed in traditional magnetic tunnel junctions (MTJs) and developing van der Waals (vdW) MTJs based on 2D materials. In this research, based on first-principles calculations associated with non-equilibrium Green’s function, we investigated a class of vdW MTJs based on ferromagnetic CrBr₃ monolayer, namely 1 T-TMX₂/CrBr₃/NM spacer/CrBr₃/1T-TMX₂ vdW MTJs (TM = Mo, W; X = S, Se). Most importantly, we determined that the vdW MTJ (marked as MTJ4) with 1 T-MoSe₂ and 2H-MoS₂ as electrodes and NM spacer respectively, is the most favorable model for achieving excellent spin-filtering (P_MTJ = 99.98 %) and huge TMR ratio (4.07 × 10⁵ %). Analyses of real space projected LDOS, layer-dependent DOS, and differential charge densities further revealed that huge TMR effect of MTJ4 comes from the spin-dependent transmission barrier due to half-metallic CrBr₃ induced by charge transfer at 1 T-MoSe₂/CrBr₃ interface. Moreover, robustness of high-performance spin transport in MTJ4 at small bias voltages was also verified. Our work suggests that 2D CrBr₃ ferromagnet possesses promising prospects in low-dimensional spintronic devices. Our research also paves the way for experimentally designing and manufacturing high-performance 2D vdW MTJs.