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High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
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Phononic topological insulators based on six-petal holey silicon structures
Ziqi Yu1, Zongqing Ren1, Jaeho Lee2
1Mechanical and Aerospace Engineering, University of California, Irvine, Irvine, 92697, USA.
Scientific Reports
|February 14, 2019
Summary
Researchers developed a novel holey silicon phononic crystal, enabling robust, topologically protected elastic wave propagation. This breakthrough advances phononic circuits by overcoming challenges in creating topological states in solids.
Area of Science:
- Solid-state physics
- Acoustics
- Materials science
Background:
- Topological insulators have advanced in electronics and photonics, but phononic topological insulators in solids remain underexplored.
- Challenges include realizing topological states without spin-like degrees of freedom and managing transverse phonon polarizations.
Purpose of the Study:
- To present a novel holey silicon-based topological insulator design.
- To enable topologically protected in-plane elastic wave propagation in solids.
Main Methods:
- Geometric control of a hexagonal lattice of holes in silicon.
- Inducing zone folding to form a double Dirac cone.
- Breaking discrete translational symmetry to achieve topological phase transition.
Main Results:
- Demonstrated topologically protected in-plane elastic wave propagation up to GHz ranges.
- Confirmed inverted band structures and backscattering-immune wave transmission through defects.
- Showcased robustness against geometric errors, with up to 90% transmission despite hole size variations.
Conclusions:
- Established a relationship between geometry and topological properties in phononic crystals.
- Paved the way for developing future phononic circuits with protected wave propagation.
- Highlighted the potential of holey silicon as a platform for phononic topological insulators.
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