Electrical-controlled and layer-filtered altermagnetic tunnel junction with all-in-one architecture

Abstract

Altermagnets (AMs) offer a rare combination of zero net magnetization and non-relativistic spin splitting. However, achieving efficient switching of AM states remains a critical challenge for practical spintronic devices. Here, based on the finding that the external out-of-plane electric field lifts the band degeneracy of bilayer V2Se2O and hosts layer-dependent spin polarization at the Fermi level, we propose a scheme to achieve an all-electric-controlled AM tunnel junction solely with the bilayer V2Se2O via the first-principles quantum transport calculations. As the electric field applied to two ends switches from the same direction to the opposite direction, two prominent conduction states can be achieved, leading to a tunneling magnetoresistance as high as ∼1010%. Notably, the transport channels are layer-filtered, that is, only the bottom layer contributes to the tunneling unless the spin-splitting bands from the conduction and the valence bands cross together when the electric field increases to 0.25 V/Å. Our findings provide theoretical guidance for utilizing AM bilayers in low-power, high-speed memory devices and highlight a feasible route for the electrical manipulation of layer-resolved AM transport.