Giant tunneling magnetoresistance driven by momentum-selective resonant tunneling in double-barrier altermagnetic tunnel junctions
Phys. Rev. B 114, 084405 – Published 7 August, 2026
DOI: https://doi.org/10.1103/h13n-whcx
Abstract
Altermagnets, characterized by vanishing net magnetization and momentum-dependent spin-splitting, offer a unique platform for high-performance spintronic devices. Here, we propose a double-barrier altermagnetic tunneling junction, and investigate the spin transport properties of by using first-principles calculations combined with the nonequilibrium Green's function method. A giant tunneling magnetoresistance (TMR) of up to 75 094% is achieved at optimal geometry, which is much higher than that of for the single-barrier altermagnetic tunneling junction of . The transport is governed by momentum-selective resonant tunneling through quantum-well (QW) states formed in the altermagnetic spacer. Due to the intrinsic -dependent spin splitting of , the resonance condition is satisfied at distinct points for different spin channels, giving rise to localized transmission hot spots near the Brillouin-zone corners. In the parallel configuration, these QW states align with the Fermi level and support near-unity transmission, whereas reversing the Néel vector disrupts the resonance condition and suppresses transmission across the Brillouin zone, leading to the large TMR. By analyzing the dependence on QW thickness and barrier thickness, we show that the transport is controlled by the interplay of quantum confinement, total broadening, and coupling symmetry. High transmission is achieved when the QW states are properly aligned and the coupling to the electrodes is both strong and symmetric. These results provide a microscopic understanding of altermagnetism-driven resonant tunneling and offer a route to enhancing TMR through momentum-selective transport.
