Acoustic topological phase transition induced by band inversion of high-order compound modes and robust pseudospin-dependent transport?

• 作者: Xia Zhang Yan Li Yi-Nuo Liu
• 来源期刊: 中国物理B（英文版）
• 年，卷（期）: 2020,（10）
• 所属期刊栏目: CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
• 页码范围: 504-511
• 页数: 8页
• 语种: 英文
• DOI: 10.1088/1674-1056/abad21

摘要

A simple two-dimensional phononic crystal hosting topologically protected edge states is proposed to emulate the quantum spin Hall effect in electronic systems, whose phononic topological phase can be reconfigured through the rotation of scatters. In particular, the band inversion occurs between two pairs of high-order compound states, resulting in topo-logical phase transition from trivial to nontrivial over a relatively broad high-frequency range. This is further evidenced by an effective Hamiltonian derived by the k · p perturbation theory. The phononic topology is related to a pseudo-time-reversal symmetry constructed by the point group symmetry of two doubly degenerate eigenstates. Numerical simulations unambiguously demonstrate robust helical edge states whose pseudospin indices are locked to the propagation direction along the interface between topologically trivial and nontrivial phononic crystals. Our designed phononic systems provide potential applications in robust acoustic signal transport along any desired path over a high-frequency range.