We present fine momentum space resolution resonant elastic x-ray scattering measurements of the magnetic structure of the metallic antiferromagnet CoNb3S6. Using circular dichroism and full linear polarization analysis of the magnetic scattering, we reveal a non-coplanar double-Q (2Q) order, with a non-collinear commensurate component and a long-wavelength incommensurate helical component. This 2Q structure exhibits a staggered scalar spin chirality that forms a modulated stripe-like pattern with no uniform component. This novel magnetic order is naturally explained by the presence of four-spin exchange interactions and exhibits a complex domain structure that suggests a lowering of the structural symmetry. A symmetry analysis indicates that the 2Q order enables a finite anomalous Hall effect in CoNb3S6. In addition to identifying a novel type of magnetic ordering and its origin, our results provide insight into the mechanism of the unconventional magnetotransport phenomena in CoNb3S6 and thus identifies potential routes for realizing novel electronic phenomena in metallic antiferromagnets.
@article{arxiv.2307.03776,
title = {Double-$Q$ chiral stripe order in the anomalous Hall antiferromagnet CoNb$_3$S$_6$},
author = {Ben Zager and Shang-Shun Zhang and Hana Schiff and Raymond Fan and Paul Steadman and Cristian Batista and Kemp Plumb},
journal= {arXiv preprint arXiv:2307.03776},
year = {2026}
}