Fig. 2: Topological surface on yz-domain wall.
From: Acoustic analogues of three-dimensional topological insulators
a Picture of the experimental sample constructed by four rhomb–prisms. Each segment has 7 × 7 × 7 unit cells (e.g. a yellow rhomb–prism). The inset shows a top-down view of the zigzag interface. b Projected bandstructures in the kyz plane, where the red lines represent the gapless Dirac-like surface states. The inset shows the highly symmetric directions of the surface Brillouin zone. c 3D view of the simulated surface Dirac cone. d Measured transmission spectra for the domain wall (red) and the bulk (blue) along the \(\tilde \Gamma \tilde Y\) direction. The dashed box indicates the frequency range of the bulk bandgap. e Measured transmission spectra for a 60° bend (cyan), a 120° bend (magenta), and a splitter configuration (grey). f Slices of the simulated acoustic pressure distribution at a frequency of 5.8 kHz, where the colour scale represents the absolute value of acoustic pressure (P).
