Interface-controlled antiferromagnetic tunnel junctions

Magnetic tunnel junctions (MTJs) are essential components of high-performance spintronic devices. While conventional MTJs use ferromagnetic materials, antiferromagnetic (AFM) compounds can significantly increase operation speed and packing density. Current AFM tunnel junctions (AFMTJs) exploit antiferromagnets as spin-filter barriers or metal electrodes with bulk spin-dependent currents. Here, we highlight a largely overlooked AFMTJ prototype with bulk-spin-degenerate electrodes exhibiting A-type AFM stacking, forming magnetically uncompensated interfaces that enable spin-polarized tunneling currents and a sizable tunneling magnetoresistance (TMR). Using first-principles quantum-transport calculations and van der Waals (vdW) metal Fe 4 GeTe 2 as an example, we demonstrate a large negative TMR from interfacial magnetic moment alignment. This prototype can also be realized with non-vdW A-type AFM metals featuring roughness-insensitive surface magnetization. Beyond TMR, these AFMTJs allow convenient switching of the Néel vector, opening new avenues for AFM spintronics based on interface-driven spin-dependent properties.