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.
@article{arxiv.2605.18429,
title = {Direction-selective triplet pairing and spin-edge locking in altermagnetic metals},
author = {Lie Yuan and Junkang Huang and Yu-Xuan Li and Tao Zhou},
journal= {arXiv preprint arXiv:2605.18429},
year = {2026}
}