Width-dependent spintronic properties in graphene/h-BN nanoribbon-based magnetic tunnel junctions: a first-principles study

Abstract Magnetic tunnel junctions (MTJs) based on low-dimensional materials offer promising potential for low-power consumption and highly efficient spintronics applications. In this study, we investigate width-dependent electric transport properties in lateral heterostructures consisting of zigzag graphene nanoribbons (ZGNRs) as ferromagnetic layers and hexagonal boron nitride (h-BN) as a tunnel barrier. Four models of MTJs, n -ZGNR, are constructed with varying ribbon widths n = 6, 8, 10, and 12. First-principles calculations using density functional theory (DFT) combined with the nonequilibrium Green’s function (NEGF) formalism are employed to examine the spintronic performances. Our analysis reveals that the band structures of the leads remain metallic for all variations. We also obtain that the wider ribbon exhibits an exceptional TMR ratio, while the narrower one shows a great spin filtering under low bias voltage. This study is proposed to design potential candidates for highly efficient and energy-saving MTJs-based spintronics devices.