Dirac cones in two-dimensional artificial crystals for classical waves
Dirac cones in two-dimensional artificial crystals for classical waves
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二维人造晶体中经典波的狄拉克锥
DOI：
10.1103/physrevb.89.134302
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发表时间：
2014-04-04
影响因子：
3.7
通讯作者：
Liu, Zhengyou
中科院分区：
文献类型：
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作者：
Lu, Jiuyang;Qiu, Chunyin;Liu, Zhengyou
研究了二维声子晶体中狄拉克锥的存在。具体地说，我们从声子晶体开始，这些声子晶体由排列在六角形晶格中的可旋转的规则六边形或三角形棒组成。额外的旋转自由度使晶体具有各种对称性。数值和实验的能带结构一致地表明，部分对称性可以稳定地支撑狄拉克锥，而其他对称性则不能。用k·p微扰理论和对称性分析相结合的方法成功地解释了这些现象。在此理论框架的基础上，进一步对对称性进行了系统的探讨，对狄拉克锥的存在进行了全面的总结。这一结论也适用于经典波的其他类型的人工晶体，无论是标量波还是矢量波。
We present a study on the existence of Dirac cones in two-dimensional phononic crystals. Specifically, we start from the phononic crystals made of rotatable regular hexagonal or triangular rods arranged in a hexagonal lattice. The additional freedom of the rotation enables the crystals with various symmetries. The numerical and experimental band structures manifest consistently that part of the symmetries can support Dirac cones stably, yet the others cannot. The phenomena are explained successfully by the k · p perturbation theory combined with symmetry analysis. Based on this theoretical framework, a systemic exploration on symmetry is further performed, which yields a complete summary on the existence of Dirac cones. The conclusion also remains in the other types of artificial crystals for classical waves, either scalar or vectorial ones.