Magnetic Weyl Semimetal in Quasi Two-dimensional Half Metallic Co₃Sn₂S₂

A Weyl semimetal can exist in a time reversal or inversion symmetry breaking system. Since the Berry curvature is odd under time reversal, the Berry curvature from Weyl points are expected to generate a large anomalous Hall effect in time reversal symmetry breaking Weyl semimetals. In this work, we find a Weyl semimetal phase in half metallic ferromagnet Co₃Sn₂S₂ with Weyl points only 60 meV away from the Fermi level, which derive from nodal lines that are gapped by spin-orbit coupling. Therefore, the Weyl-related physics should be easy to detected by both ARPES and bulk transport measurements. Due to the Berry curvature deriving from the gapped nodal lines and Weyl points, its anomalous Hall conductivity can reach up to 1200 S/cm. Substituting S by Se, Co₃Sn₂Se₂ shows very similar property. Moreover, since Co₃Sn₂S₂ is easily grown quasi two-dimensional compound, it provides an ideal platform for the study of magnetic Weyl physics and its future application in topological material based spintronic devices.