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arXiv · 2605.25369

Effects of Band Symmetry on Spin-Dependent Transport in Noncollinear Antiferromagnetic Tunnel Junctions

Mohamed Elekhtiar·Ding-Fu Shao·Evgeny Y. Tsymbal
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Abstract

Antiferromagnetic tunnel junctions (AFMTJs) can exhibit large tunneling magnetoresistance (TMR), making them promising candidates for ultrafast and field-robust spintronic devices. Here, we elucidate the role of band symmetry in governing spin-dependent transport in AFMTJs. Using first-principles density-functional theory combined with quantum-transport calculations, we investigate Mn3NiN/LaAlO3/Mn3NiN (001) junctions based on the noncollinear $\Gamma_{4g}$ antiferromagnetic phase of Mn3NiN. Although Mn3NiN exhibits a large momentum-dependent spin polarization due to broken $PT$ symmetry, we show that the tunneling conductance is critically controlled by band symmetry of the electrode Bloch states and their symmetry-selective coupling to evanescent states in the LaAlO3 barrier. Orbital-symmetry selection rules suppress interband transmission in the parallel configuration, whereas the antiparallel configuration enables symmetry-compatible interband tunneling along the diagonal directions of the two-dimensional Brillouin zone. These additional transmission channels enhance the antiparallel conductance and reduce the TMR relative to predictions based solely on spin polarization. Nevertheless, the TMR remains exceptionally large, exceeding 2000%, while band symmetry controls the attainable magnitude of TMR in AFMTJs. Our results establish band-symmetry filtering as an essential ingredient of spin-dependent tunneling in AFMTJs.

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Mohamed Elekhtiar, Ding-Fu Shao, Evgeny Y. Tsymbal. 2026-05-25. Effects of Band Symmetry on Spin-Dependent Transport in Noncollinear Antiferromagnetic Tunnel Junctions. https://arxiv.org/abs/2605.25369

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