Unconventional alternating out-of-plane spin polarization in the coplanar kagome antiferromagnet

TL;DR

This paper demonstrates that a noncollinear kagome antiferromagnet can produce alternating out-of-plane spin polarization and spin-polarized edge states without relying on relativistic spin--orbit coupling, influenced by magnetic symmetry and confinement.

Contribution

It reveals a novel mechanism for generating spin-polarized currents in coplanar antiferromagnets through magnetic symmetry and confinement effects, independent of relativistic interactions.

Findings

Noncollinear kagome antiferromagnet exhibits alternating out-of-plane spin polarization.

Spatial confinement leads to distinct real-space spin separation patterns.

Breaking mirror symmetry induces altermagnetic-like spin splitting and spin--edge locking.

Abstract

The emergence of spin-polarized currents in nonrelativistic platforms continues to attract significant interest in spintronics. Here we demonstrate that a noncollinear kagome antiferromagnet can generate an alternating out-of-plane spin polarization originating from the spin chirality of the magnetic unit cell, in the absence of relativistic spin--orbit coupling. Under spatial confinement, the system develops distinct real-space spin separation patterns whose structure is governed by the symmetry of the lattice termination. In particular, breaking the transverse mirror symmetry of the ribbon produces an altermagnetic-like spin splitting in the band structure. Furthermore, we uncover a spin--edge locking mechanism in which propagating edge states acquire an unconventional spin polarization. These results highlight how magnetic symmetry and confinement can generate spin-polarized transport in coplanar antiferromagnets without relying on relativistic interactions.