Fig. 1: 3D chirally stacked acoustic metacrystal with multiple Weyl points.
From: Observation of quadratic Weyl points and double-helicoid arcs
a An image of the sample and its unit-cell geometry. b Band structure calculated along several high-symmetry lines, where the color spheres highlight the differently charged topological nodes provided by the lowest three bands (color lines). c Bulk BZ of the metacrystal. d Local dispersions simulated around the four nodal points, revealing clearly the quadratic dispersions near the QWPs \({\mathrm{\Gamma }}\) and \({\mathrm{A}}\), along the \(k_x\) and \(k_y\) directions, in contrast to the CWPs \({\mathrm{K}}\) and \({\mathrm{H}}\) crossed linearly along all directions.
