人工带隙材料的拓扑性质

Topological properties of artificial bandgap materials

近年来,人工带隙材料(如声子晶体和光子晶体)由于其优异的性能,已成为新一代智能材料的研究焦点.另一方面,材料拓扑学由凝聚态物理领域逐渐延伸到其他粒子或准粒子系统,而研究人工带隙材料的拓扑性质更是受到人们的广泛关注,其特有的鲁棒边界态,具有缺陷免疫、背散射抑制和自旋轨道锁定的传输等特性,潜在应用前景巨大.本文简要介绍拓扑材料特有的鲁棒边界态的物理图像及其物理意义,并列举诸如光/声量子霍尔效应、量子自旋霍尔效应、Floquet拓扑绝缘体等相关工作;利用Dirac方程,从原理上分析光/声拓扑性质的由来;最后对相关领域的发展方向和应用前景进行了相应的讨论.

Recently, artificial bandgap materials（such as photonic crystals and phononic crystals） have been becoming the research hotspot of the next generation intelligent materials, because of its extremely designable, tunable and controllable capacity of classical waves. On the other hand, topological material phase, originally proposed and first demonstrated in Fermionic electronic systems, has been proposed in more and more Bosonic systems. In this review paper, we first focus on some of the representative photonic/phononic topological models, and four common types of topological photonic system are discussed： 1） photonic/phononic quantum Hall effect with broken time-reversal symmetry; 2） photonic topological insulator and the associated pseudo-time-reversal symmetry protected mechanism; 3） time/space periodically modulated photonic Floquet topological insulator; 4） a summary and outlook including a brief introduction of Zak phase in onedimensional systems and Weyl point in three-dimensional systems. Finally, the underlying Dirac model is analyzed.