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arXiv · 2607.25213

Stacking-dependent anisotropic altermagnetism in V$_{1/3}$NbS$_2$

Chris J. Lygouras·Nathan Prouse·Jack H. Drouin·Youzhe Chen·Laura Garcia-Gassull·Zili Feng·Mingxuan Fu·Lü Fang·Alexander I. Kolesnikov·Christina Hoffman·Yiqing Hao·Huibo Cao·Maxime A. Siegler·Robert J. Birgeneau·Roser Valentí·Satoru Nakatsuji·Collin L. Broholm
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Abstract

We report profound impacts of the stacking sequence of triangular lattices of magnetic transition metal ions intercalated between the layers of the van der Waals material NbS$_2$. Using single crystal x-ray and neutron diffraction, and transport and magnetization measurements, we show there are two distinct polytypes of $\rm V_{1/3}NbS_2$ with disparate easy axes of magnetization and different anomalous Hall responses. Self-consistent analysis of inelastic neutron scattering data provides evidence for oscillatory RKKY interactions that extend to 1 nm and stabilize quasi-collinear A-type altermagnetic orders in both polytypes though with perpendicular easy axes. The detailed stacking sequence of a bulk polytype crystal dramatically impact its macroscopic anomalous Hall response and magnetism, which suggests a new path to engineer the bulk properties of a layered three dimensional solid.

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Chris J. Lygouras, Nathan Prouse, Jack H. Drouin, Youzhe Chen, Laura Garcia-Gassull, Zili Feng, Mingxuan Fu, Lü Fang, Alexander I. Kolesnikov, Christina Hoffman, Yiqing Hao, Huibo Cao, Maxime A. Siegler, Robert J. Birgeneau, Roser Valentí, Satoru Nakatsuji, Collin L. Broholm. 2026-07-28. Stacking-dependent anisotropic altermagnetism in V$_{1/3}$NbS$_2$. https://arxiv.org/abs/2607.25213

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