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arXiv · 2603.00739

Coupled Real- and Momentum-Space Topology in Symmetry-Locked Bilayer Altermagnet

Shuo Zhang·Zijie Fu·Lixiu Guan·Yirui Du·Linyang Li·Junguang Tao
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Abstract

Integrating real-space topological spin textures with momentum-space topological electronic states within a single altermagnetic system has remained a persistent challenge. Here, we introduce a symmetry-locked bilayer altermagnet that concurrently hosts d-wave altermagnetism, momentum-space topology, and stable antiskyrmions. In momentum-space, it enables strain-triggered transitions to an antiferromagnetic Weyl semimetal phase, where the N\'eel vector acts as a switch for spin-layer-polarized quantum anomalous Hall and Weyl states, alongside coupled topological states and valley polarization effects. In real-space, the formation of interlayer co-directional and locked in-plane Dzyaloshinskii-Moriya interactions facilitates the creation of coupled antiskyrmion pairs with compensated topological charges. This locking symmetry fully cancels the transverse Magnus forces, resulting in current-driven, strictly longitudinal motion of antiskyrmions without any Hall-like deflection. Our work establishes a robust platform for dual-space topological magnetism and offers a definitive solution to the vanishing Hall angle in charge-neutral antiskyrmions, opening pathways toward high-density, low-power topological spintronics.

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Shuo Zhang, Zijie Fu, Lixiu Guan, Yirui Du, Linyang Li, Junguang Tao. 2026-02-28. Coupled Real- and Momentum-Space Topology in Symmetry-Locked Bilayer Altermagnet. https://arxiv.org/abs/2603.00739

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