Fig. 2: Synthetic acoustic Weyl semimetal.
From: Observation of chiral Landau levels in a synthetic acoustic Weyl semimetal
a Illustration of the primitive cell of a 2D triangular sonic crystal composed of cylindrical scatterers (blue) in an air matrix (gray). b Phase diagram for the effective mass term Δm and the band gap width while scanning the synthetic degree of freedom θ. c The synthetic 3D Brillouin zone (BZ), in which the red and blue dots denote the synthetic Weyl points (WPs) with topological charges of  +1 and  −1, respectively. d Calculated band diagram of the synthetic acoustic weyl semimetal. Blue shadowed regions represent the scanning paths traversing the synthetic axis kz(θ).
