Acoustic valley edge states in a graphene-like resonator system

The concept of valley physics, as inspired by the recent development in valleytronic materials, has been extended to acoustic crystals for manipulation of air-borne sound. Many valleytronic materials follow the model of a gapped graphene. Yet the previously demonstrated valley acoustic crystal adopt...

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Bibliographic Details
Published in:Journal of applied physics 2018-03, Vol.123 (9)
Main Authors: Yang, Yahui, Yang, Zhaoju, Zhang, Baile
Format: Article
Language:English
Subjects:
Acoustics
Applied physics
Broken symmetry
Computer simulation
Condensed matter physics
Domain walls
Graphene
Resonators
Sound waves
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Summary:The concept of valley physics, as inspired by the recent development in valleytronic materials, has been extended to acoustic crystals for manipulation of air-borne sound. Many valleytronic materials follow the model of a gapped graphene. Yet the previously demonstrated valley acoustic crystal adopted a mirror-symmetry-breaking mechanism, lacking a direct counterpart in condensed matter systems. In this paper, we investigate a two-dimensional (2D) periodic acoustic resonator system with inversion symmetry breaking, as an analogue of a gapped graphene monolayer. It demonstrates the quantum valley Hall topological phase for sound waves. Similar to a gapped graphene, gapless topological valley edge states can be found at a zigzag domain wall separating different domains with opposite valley Chern numbers, while an armchair domain wall hosts no gapless edge states. Our study offers a route to simulate novel valley phenomena predicted in gapped graphene and other 2D materials with classical acoustic waves.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.5009626