Underwater acoustic metamaterial based on double Dirac cone characteristics in rectangular phononic crystals<xref rid="cpb_28_12_124301fn1" ref-type="fn">*</xref><fn id="cpb_28_12_124301fn1"><label>*</label><p>Project supported by the National Natural Science Foundation of China (Grant Nos. 11602269, 11972034, and 11802213), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB22040301), and the Research Program of Beijing, China (Grant Nos. Z161100002616034 and Z171100000817010).</p></fn>

Underwater acoustic metamaterial based on double Dirac cone characteristics in rectangular phononic crystals**

Project supported by the National Natural Science Foundation of China (Grant Nos. 11602269, 11972034, and 11802213), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB22040301), and the Research Program of Beijing, China (Grant Nos. Z161100002616034 and Z171100000817010).

Pei Dong-Liang^{1, 2}, Yang Tao^{1, 2}, Chen Meng^{1, 2, †}, Jiang Heng^{1, 2, ‡}

(a) Band structure of a V-type PC when θ is −20°, 0°, and 20° respectively. (b) Variation of q and p states with rotation angle θ increasing from −30° to 30°, the inset shows the distribution of sound pressure of q and p states when θ = ±20°. (c) Band structure of a T-type PC when θ is −60°, 0°, and 60° respectively. (d) Variation of q and p states with θ increasing from −90° to 90° for the T-type PC, the inset shows the distribution of sound pressure of q and p states when θ = ± 60°.