Figure 3: Double Weyl points breaking into single Weyl points due to symmetry breaking.
(a) Unit cell of the crystal breaking C3 symmetry where the PEC cylinder in is replaced by an elliptical cylinder.(b) Corresponding Brillouin zone. Blue solid line highlights the path of the k-point when calculating the dispersion in (c). The upper M point, which is related to the lower M point by a reciprocal lattice vector, lies on the Γ−K′ direction. (c) Band structure in the plane of kz=0. Each of the three double Weyl points at Γ splits into two single Weyl points. Only three of the six single Weyl points are shown (the band crossing points between the second and third bands, the fourth and fifth bands, and the sixth and seventh bands). The other three single Weyl points can be inferred by applying C2 rotation about the axis of the elliptical cylinder. (d) and (e) show the linear dispersions near the Weyl point between the fourth and fifth bands along the y and z directions, respectively. Interestingly, this tilted Weyl point at 10.6 GHz is in fact a type-II Weyl point having a finite density of states.
