Open AccessSwitching between deterministic and accidental Dirac degeneracy by rotating scatterers and the multi-channel topological transport of sound
Author(s) -
Xiang Xie,
Honglang Li,
YuGui Peng,
Xuefeng Zhu,
Wei Luo,
Degang Zhao
Publication year - 2019
Publication title -
new journal of physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.584
H-Index - 190
ISSN - 1367-2630
DOI - 10.1088/1367-2630/ab2efe
Subject(s) - physics , brillouin zone , topology (electrical circuits) , dirac (video compression format) , phase transition , point reflection , condensed matter physics , quantum mechanics , mathematics , combinatorics , neutrino
In this study, a Dirac cone is yielded at the corner of the Brillouin zone of a two-dimensional solid phononic crystal, which consists of a triangular array of hexagonal steel with a trilobal hole drilled in the center. With the rotation of the trilobal hole, the Dirac degeneracy switches between the deterministic form and accidental form. Every Dirac point is the critical state of a topological phase transition process, which occurs six times within an angular period of 120 ° . This structure offers a flexible way to achieve topological transitions and provides multiple routes to construct an interface that supports valley-dependent edge states between two topologically distinct PCs. The associated backscattering suppressed wave propagation along the multiple curved interface channels is also demonstrated. In addition, our design shows the robust propagation of topological interface states against the perturbation of the structure. This study could potentially be significant in the design of acoustic devices for practical applications, such as acoustic signal lossless transport and tunable multi-channel sound transmission.