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Updated: Sep 19, 2025
Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
Three-Dimensional Valley Hall Phases in Phononic Crystals.
Riyi Zheng1, Jialuo Liang1, Junpeng Wu1
1South China University of Technology, School of Physics and Optoelectronics, Guangzhou 510640, China.
This study generalizes two-dimensional Valley Hall phases (VHPs) to three-dimensional phononic crystals, enabling novel topological surface states and wave manipulations. These 3D VHPs open new avenues for designing advanced acoustic devices.
Area of Science:
- Condensed Matter Physics
- Topological Materials
- Acoustics
Background:
- Valley Hall phases (VHPs) are known for wave manipulation in 2D systems.
- Extending VHPs to 3D platforms presents significant challenges and remains an open question.
Purpose of the Study:
- To generalize 2D Valley Hall phases to 3D phononic crystals.
- To explore novel topological phenomena and wave propagation in 3D systems.
Main Methods:
- Utilizing nodal-line semimetal-derived phononic crystals.
- Manipulating geometric parameters to induce band inversion and generate VHPs.
- Investigating topological surface states protected by 3-tuple valley Chern numbers.
Main Results:
- Two distinct 3D VHPs were generated with opposite Berry curvature distributions.
- Topological surface states emerged at interfaces between different VHPs.
- Experimental observation of intriguing surface wave propagations, including negative refraction and circular propagation at corners.
Conclusions:
- The generalization of VHPs to 3D phononic crystals is achieved.
- 3D VHPs support topological surface states and exhibit unique wave behaviors.
- This work provides a foundation for designing 3D acoustic devices with advanced functionalities.
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