Fig. 3: Numerical evidence for the topological charges of QWPs through nontrivial surface states.
From: Observation of quadratic Weyl points and double-helicoid arcs
a Bulk BZ and its surface projection to the \(k_x\)–\(k_z\) plane. The black circle (of radius \(0.2\pi /a\)) is the projection of the orange tube surrounding the QWP at \({\mathrm{\Gamma }}\). b Projected band structure along the circular path in a. The color shadows are the projections of different bulk bands, the red solid lines indicate the presence of topological surface states, and the blue dashed line labels the frequency of the Weyl node at \({\mathrm{\Gamma }}\). c–e Similar to b, but for the paths each encircling a different Weyl node from Fig. 1b. The red dashed line in d corresponds to topologically trivial surface states.
