Topological phononic crystals (PCs) as a novel and hot research of topological phases of matter have attracted increasing attention due to the topological transport characteristics of elastic waves. However, the effectively multi-field realization and regulation of elastic waves topological transport in complex environments remains a challenge. This study designs a novel magnetostrictive PC plate composed of magnetostrictive pillars periodically arranged on an elastic subplate aiming to dynamically manipulate topological transport of valley Hall interface state for flexural waves by applied multi-field loadings. First, the Dirac phase transition and broadband Dirac point can be successfully induced by simply controlling the local magnetic and thermal fields according to the nonlinear magneto-mechanical-thermal coupling behaviors of magnetostrictive materials. Subsequently, the reconfigurable topological transport and beam splitter of valley Hall interface state of flexural waves can be obviously observed at the interface of the proposed PC system by adjusted multi-field loadings. The results show that the arbitrary topological transport route and splitting ratio of beam splitter can be dynamically tuned by adjusting the magnetic and thermal loadings. In addition, the robustness of flexural waves topological transport to the defects is investigated. Finally, the experimental verification of reconfigurable topological transport for flexural waves is studied under multi-field environments. This study can provide an effective guidance for actively controlling topological transport of elastic waves and be beneficial for the sophisticated and customized design of novel topological devices.

中文翻译：

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磁致伸缩声子晶体中弹性波的多场诱导可重构拓扑传输

拓扑声子晶体 （PCs） 作为一种新型的热门物质拓扑相研究，由于弹性波的拓扑输运特性而受到越来越多的关注。然而，在复杂环境中有效实现和调控弹性波拓扑输运的多场仍然是一个挑战。本研究设计了一种新型磁致伸缩 PC 板，由周期性排列在弹性子板上的磁致伸缩柱组成，旨在通过施加多场载荷动态纵弯曲波谷霍尔界面状态的拓扑传输。首先，根据磁致伸缩材料的非线性磁-机械-热耦合行为，只需控制局部磁场和热场，就可以成功诱导狄拉克相变和宽带狄拉克点。随后，通过调整多场载荷，可以在所提出的 PC 系统的界面处明显观察到弯曲波的可重构拓扑传输和分束器。结果表明，通过调整磁载荷和热载荷，可以动态调节分束器的任意拓扑传输路线和分束比。此外，还研究了弯曲波拓扑输运到缺陷的鲁棒性。最后，研究了多场环境下弯曲波可重构拓扑输运的实验验证。该研究可为主动控制弹性波的拓扑输运提供有效的指导，有利于新型拓扑器件的复杂化和定制化设计。