Fig. 4: Experimental observation of the chiral Landau levels (LLs).
From: Observation of chiral Landau levels in a synthetic acoustic Weyl semimetal
a Photo of a fabricated 2D sonic crystal composed of 20a × 20a units, where the pseudo-magnetic field (PMF) is engineered by the gradient deformations along the y direction. Right-top inset shows the structure designed for small angle adjustment of θ, which consists of a nonagonal base and a octagonal disk with the structural parameters provided in Supplementary Note 3. b Distributions of the deformations η with respect to the y direction. Solid line shows the theoretical result and the brown triangles represent the values selected to design the structure. c The corresponding positions' shift Δk of the Weyl points (WPs) at different places. d, e Experimentally measured projected dispersions of the chiral LLs near the WPs W1 (d) and W2 (e). The curves denote the simulated results. f, g Frequency spectra for the total sound intensity measured at all sub-lattices p (blue) and q (red) while excited by a point source placed at the position q (f) and p (g) near the sample center.
