Weyl-node-driven domain wall motion and collective magnetism in double-symmetry-breaking Weyl semimetals*

In the RAlX (R = rare-earths, X = Ge/Si) material family where both inversion and time-reversal symmetry are broken, not only the magnetic Weyl nodes are stabilized, but also interesting interactions are enabled and can lead to new Weyl physics [1-8]. The abundance of robust magnetic Weyl semimetals in the RAlX family allows for domain wall motion and collective magnetism related to Weyl nodes to emerge. We give an overview of rich domain wall physics in different RAlX materials revealed by scanning SQUID microscopy [3, 4], magneto-optical Kerr effect [5], and small-angle neutron scattering [6], and Weyl-mediated magnetism detected by neutron diffraction [6, 7]. In particular, we highlight the unusual electrical transport driven by domain walls and Weyl nodes [6, 8], and collective magnetism driven by Weyl-mediated interactions [7]. We demonstrate that the double-symmetry-breaking RAlX family is a promising avenue for new Weyl physics.