Magnetic Weyl semimetals

Abstract

Topological Matter Weyl semimetals (WSMs)—materials that host exotic quasiparticles called Weyl fermions—must break either spatial inversion or time-reversal symmetry. A number of WSMs that break inversion symmetry have been identified, but showing unambiguously that a material is a time-reversal-breaking WSM is tricky. Three groups now provide spectroscopic evidence for this latter state in magnetic materials (see the Perspective by da Silva Neto). Belopolski et al. probed the material Co2MnGa using angle-resolved photoemission spectroscopy, revealing exotic drumhead surface states. Using the same technique, Liu et al. studied the material Co3Sn2S2, which was complemented by the scanning tunneling spectroscopy measurements of Morali et al. These magnetic WSM states provide an ideal setting for exotic transport effects. Science , this issue p. [1278][1], p. [1282][2], p. [1286][3]; see also p. [1248][4] [1]: /lookup/doi/10.1126/science.aav2327 [2]: /lookup/doi/10.1126/science.aav2873 [3]: /lookup/doi/10.1126/science.aav2334 [4]: /lookup/doi/10.1126/science.aax6190