Topological Moiré Polaritons

Area of Science:

• Photonics
• Condensed Matter Physics
• Topological Materials

Background:

• Bilayer graphene exhibits unique electronic properties due to its band structure.
• Photonic systems can emulate condensed matter phenomena, offering new avenues for research.
• Spin-orbit coupling (SOC) is crucial for understanding topological properties in various physical systems.

Purpose of the Study:

• To create a tunable photonic analog of bilayer graphene.
• To investigate the control of moiré band topology using photonic SOC.
• To explore the creation and properties of topological edge states in such a system.

Main Methods:

• Utilizing an in-plane honeycomb potential combined with photonic spin-orbit coupling (SOC).
• Modulating the magnitude of SOC to alter lattice periodicity and emulate different moiré structures.
• Breaking time-reversal symmetry via exciton-polariton Zeeman splitting.

Main Results:

• Successfully emulated moiré-arranged bilayer graphene with tunable SOC.
• Achieved all-optical access to moiré band topology.
• Opened a topological gap in moiré flat bands by breaking time-reversal symmetry.
• Observed one-way topological edge states with constant group velocity.

Conclusions:

• Photonic SOC provides a powerful tool for emulating and controlling topological properties of moiré materials.
• The demonstrated system offers unique all-optical access to topological phenomena.
• The observed topological edge states exhibit distinct characteristics compared to flat bands.