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Flatbands in a bilayer surface plasmon crystal at a large twist angle due to interlayer strong coupling
Optics Letters
|August 2, 2024
Summary
Researchers created a twisted bilayer surface plasmon crystal exhibiting flatbands at a large twist angle. Adjusting geometry and separation distance enables strong interlayer coupling, crucial for flatband properties like slow light.
Area of Science:
- Photonics
- Condensed Matter Physics
- Materials Science
Background:
- Twisted bilayer systems are key for studying flatbands.
- Hexagonal boron nitride (h-BN)-like structures offer unique optical properties.
Purpose of the Study:
- To propose and investigate a bilayer surface plasmon crystal with flatbands.
- To explore the role of interlayer coupling and geometry in achieving flatbands at large twist angles.
Main Methods:
- Numerical and theoretical calculation of band structure.
- Tuning pillar radius ratio (PRR) and interlayer separation distance.
- Analysis of coupling regimes (weak vs. strong).
Main Results:
- A bilayer h-BN-like surface plasmon crystal with flatbands was achieved at a 38.213° twist angle.
- Increasing PRR and decreasing separation distance enhance interlayer coupling.
- Strong coupling leads to flatbands with slow light velocity and high density of states.
Conclusions:
- In-layer geometry and interlayer distance provide control over flatband formation.
- This work deepens the understanding of twisted bilayer photonic systems.
- Novel methods for obtaining flatbands in such systems are presented.
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