New classes of band degeneracies in magnetic materials universe

We perform a comprehensive study of band degeneracies protected by 3D magnetic space groups in the bands of magnons and of electrons, and obtain all new classes of degeneracies (nodes) that cannot appear in non-magnetic materials.
The new nodes protected by magnetic space groups are unified and classified using the group cohomology of the corresponding point group.
We propose a method to find if the effective theory of any new degeneracy has linear dispersion in all three directions, and use the method to identify all linear-dispersing nodes of four or higher degeneracy.