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Acoustic Möbius Insulators from Projective Symmetry
Tianzi Li1, Juan Du1, Qicheng Zhang1
1Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China.
Physical Review Letters
|April 1, 2022
Summary
Researchers created novel Möbius insulators in acoustic crystals, demonstrating unique topological physics through projective translation symmetry. This work introduces a new framework for topological physics in artificial systems.
Area of Science:
- Condensed Matter Physics
- Topological Materials
- Acoustic Metamaterials
Background:
- Gauge symmetry in artificial crystals requires projective representation of crystalline symmetries.
- This leads to novel topological physics phenomena.
- Möbius-twisted topological phases are a new class of such phenomena.
Purpose of the Study:
- To demonstrate the concept of projective translation symmetry in constructing topological phases.
- To experimentally realize Möbius insulators in acoustic crystals.
- To explore the unique properties of Möbius edge and hinge states.
Main Methods:
- Exploiting projective translation symmetry.
- Constructing Möbius-twisted topological phases.
- Realizing two- and three-dimensional Möbius insulators in acoustic crystals.
- Observing edge and hinge states via real-space visualization, momentum-space spectroscopy, and phase-space winding analysis.
Main Results:
- Successful realization of two Möbius insulators: a 2D first-order and a 3D higher-order topological insulator.
- Unambiguous observation of peculiar Möbius edge and hinge states.
- Experimental verification of 4π periodicity and projective translation eigenvalues.
Conclusions:
- The study opens a new avenue for artificial systems combining gauge and crystalline symmetries.
- It initializes a new framework for topological physics based on projective symmetry.
- Demonstrates the potential of acoustic crystals for realizing exotic topological states.
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