  In three-dimensional noncentrosymmetric materials two-fold screw rotation
symmetry forces electron's energy bands to have Weyl points at which two bands
touch. This is illustrated for space groups No. 19 ($P2_12_12_1$) and No. 198
($P2_13$), which have three orthogonal screw rotation axes. In the case of
space groups No. 61 ($Pbca$) and No. 205 ($P$a-3) that have extra inversion
symmetry, Weyl points are promoted to four-fold degenerate line nodes in
glide-invariant planes. The three-fold rotation symmetry present in the space
groups No. 198 and No. 205 allows Weyl and Dirac points, respectively, to
appear along its rotation axes in the Brillouin zone and generates four-fold
and six-fold degeneracy at the $\Gamma$ point and R point, respectively.
