Extreme acoustic band gaps obtained under high symmetry in 2D phononic crystals

• Published in: Journal of physics. D, Applied physics Vol. 39; no. 10; pp. 2272 - 2276
• Main Authors: Min, Ren, Wu, Fugen, Zhong, Lanhua, Zhong, Huilin, Zhong, Shao, Liu, Youyan
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 21.05.2006; Institute of Physics
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Lattice dynamics; Other topics in lattice dynamics; Physics; Water; Hexagonal lattices; Phononic crystal; Energy gap; Transition elements; Plane waves; Fill factor; Mercury; Crystal symmetry; Acoustic waves; Phononic band gap
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/39/10/041

Using the plane wave expansion method we have studied the effect of symmetry on the complete acoustic band gaps in two-dimensional binary phononic crystals including five types of straight rod arranged in hexagonal lattices. For each type of rod, two cases are considered: water rods in mercury (low-density scatters in high-density background) and mercury rods in water (high-density scatters in low-density background). The crystals'symmetry can be changed by rotating the noncircular rods, and the results show that the extreme (both the maximum and minimum) gaps at any given filling factor appear under high symmetry. So the above maximum gaps can be obtained by adjusting the rods' orientation. And the peaks of those maximum gaps are relative to the rods' rotational symmetry, the relations of which are different for the two cases with different density contrast.