Giant tunneling magnetoresistance in an MoSe₂/bilayer CrBr₃/MoSe₂ two-dimensional spin-filter magnetic tunnel junction

The discovery of two-dimensional (2D) layered intrinsic magnets provides a new platform for designing high-efficiency nanoscale magnetic tunnel junctions (MTJs) based on 2D materials. In this work, based on density functional theory associated with non-equilibrium Green's function, we devised a novel 2D spin-filter (sf)-MTJ, namely the MoSe₂/bilayer CrBr₃/MoSe₂ sf-MTJ, using metallic MoSe₂ as the electrode and a bilayer CrBr₃ semiconductor as the magnetic tunnel barrier. Compared with the commonly used 2D sf-MTJs based on few-layer CrI₃, the proposed sf-MTJ features a simple structure, extremely thin thickness as well as good chemical stability. Spin transport calculations show that this newly built sf-MTJ achieves an almost perfect spin filtering efficiency (99.7%) and an enormous tunneling magnetoresistance ratio (TMR) of up to 1.17 × 10⁵%. This excellent spin transport performance can be attributed to the strong spin-dependent transmission barrier effect in the sf-MTJ, which stems from the ferromagnetic half-metallicity of bilayer CrBr₃ in the parallel configuration induced by the substantial interfacial electron transfer between MoSe₂ and CrBr₃. In addition, it is found that when a small strain or bias voltage is applied, this new sf-MTJ maintains a favorable spin filtering effect (>99%) and a high TMR (∼10⁴%). Our findings demonstrate that the MoSe₂/bilayer CrBr₃/MoSe₂ sf-MTJ is a promising 2D spin-filter magnetic tunnel junction. This work also provides a new strategy for the design and fabrication of high-performance low-dimensional spintronic devices.