Single Pair of Weyl Points Evolve From Spin Group‐Protected Nodal Line in Half‐Metallic Ferromagnet V ₃ S ₄

Abstract Symmetry plays an essential role in classifying the phases and understanding the properties of materials. Recent discoveries have shown that certain properties of magnetic materials require further consideration of spin groups. Nevertheless, research on topological states and properties associated with spin groups is still in its infancy. In this work, a recipe is proposed to achieve the minimum number of Weyl points, i.e., a single pair of Weyl points (SP‐WPs) based on spin group and predict V 3 S 4 as an ideal half‐metallic Weyl semimetal with SP‐WPs evolved from a spin group‐protected nodal line (NL). Specifically, this NL is protected by the combination of spin group symmetry and inversion symmetry. Furthermore, spin group symmetry broken induced by spin‐orbit coupling also results in a series of Berry curvature‐related anomalous transport phenomena. The SP‐WPs near the Fermi level contribute to exceptional anomalous transport properties, where the anomalous conductivity exhibits sharp peaks at the energy level of SP‐WPs, while remaining nearly zero at other energy levels. Therefore, the work not only provides a guide to search for minimum number of Weyl points in magnetic materials but also identifies a half‐metallic material as an excellent platform for spintronic devices.