Weyl Nodes¶

In Weyl semimetal, breaking either inversion or Time reversal symmetry results in a pair of Dirac nodes separating into Weyl nodes. These Weyl nodes are monopoles of Berry curvature in the Brillouin zone, and the charge associated with such a monopole is known as its chirality. Weyl nodes must come in pairs of opposite chirality, such that the net chirality over the Brillouin zone is zero. A consequence of these bulk Weyl nodes is the existence of topological Fermi arcs on the surface of a TWS.