Discovery of magnetic Weyl semimetal

Weyl semimetal is a novel topological quantum state with emergent relativistic Weyl fermions of opposite chiralities and surface Fermi arcs in the electronic structure． Such distinct electronic structure leads to many exotic physical properties, such as chiral anomaly and quantum oscillations． Based on the symmetry broken, Weyl semimetal can be classified as inversion symmetry breaking non-magnetic Weyl semimetal, and time-reversal symmetry breaking magnetic Weyl semimetal． The latter is very sensitive to magnetic structure so that the manipulation of topological phase transition and physical properties can be induced by external magnetic or electric field． This has great potentials for applications in the field of spintronics． The kagome ferromagnet Co₃Sn₂S₂ is the first experimentally discovered magnetic Weyl semimetal． Its discovery is reviewed here, with emphasis on transport properties, theoretical calculations and measurements of electronic structures． The future of the study of the magnetic semimetal is discussed．