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arXiv · 2605.18429

Direction-selective triplet pairing and spin-edge locking in altermagnetic metals

Lie Yuan·Junkang Huang·Yu-Xuan Li·Tao Zhou
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Abstract

We investigate self-consistent unconventional superconductivity in a two-dimensional $d$-wave altermagnetic metal. We find that momentum-dependent altermagnetic spin splitting suppresses opposite-spin singlet pairing and stabilizes highly anisotropic equal-spin triplet order. In the spin-conserving limit, this directional triplet pairing gives rise to nearly dispersionless Majorana boundary states associated with effective one-dimensional topological channels. Rashba spin-orbit coupling mixes spin sectors, activates additional pairing components, and drives the system into a mixed-parity superconducting state with dispersive Majorana boundary states. The spin-resolved boundary spectra further reveal a characteristic locking between boundary orientation and spin polarization, reflecting the underlying altermagnetic symmetry. These results identify altermagnetic spin splitting as an intrinsic mechanism for selecting unconventional pairing and generating spin-resolved Majorana boundary states without external magnetic fields.

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Lie Yuan, Junkang Huang, Yu-Xuan Li, Tao Zhou. 2026-05-18. Direction-selective triplet pairing and spin-edge locking in altermagnetic metals. https://arxiv.org/abs/2605.18429

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