Designing 2D <i>h</i>-BN/MnO₂ heterostructure for enhanced spintronic MTJs: half-metallicity induction and high tunnel magnetoresistance performance

Abstract The realization of half-metallicity in two-dimensional (2D) materials has been extensively investigated to advance the development of next-generation nanospintronic devices. In this work, a theoretical study of the h -BN/MnO 2 vertical vdW heterostructure was conducted to manipulate the electronic structure of the ferromagnetic semiconductor MnO 2 . Our research reveals that because of the large potential difference at the heterojunction interface, the energy bands of the two materials are shifted, which results in the half-metallicity in monolayer MnO 2 . Furthermore, we designed an in-plane magnetic tunnel junction (MTJ) by using h -BN/MnO 2 heterostructure as the electrodes and monolayer MnO 2 as the barrier, and simulated its transport properties from density functional theory combined with nonequilibrium Green’s function. According to our calculations, the MTJ demonstrates perfect 100% spin polarization in PC owing to the single-channel conduction capability of half-metal MnO 2 . Also, we have considered the effect of the barrier width on tunnel magnetoresistance (TMR) of the MTJ. It is found that the TMR ratio can be adjusted by modifying the barrier width, with the maximum achievable value exceeding 10 8 . Moreover, the MTJ exhibits a 100% spin filtering effect in PC within the bias voltages of −0.1 ∼ 0.1 V. Our results provide valuable guidance for experimental investigations into MTJs utilizing 2D magnetic vdW materials.