Winding-number-engineered infrared topological interface with phononic materials cavity.

Area of Science:

• Condensed Matter Physics
• Nanophotonics
• Materials Science

Background:

• Topological phase transitions offer unique properties for wave manipulation.
• Phonon materials like Aluminum Nitride (AlN) are promising for optical applications.
• Controlling thermal radiation is crucial for various technological advancements.

Purpose of the Study:

• To present a stepped AlN/SiO2/Au cavity structure for topological phase transitions.
• To investigate the excitation and characteristics of spin-locked topological edge states.
• To explore spatial control of infrared thermal radiation using phononic materials.

Main Methods:

• Utilized a stepped AlN/SiO2/Au cavity structure.
• Analyzed reflective topological characteristics using the winding number.
• Employed Finite Element Method (FEM) simulations for edge state analysis.
• Performed Fourier transform analysis for field distribution verification.

Main Results:

• Achieved topological phase transitions by tuning the AlN layer thickness.
• Observed excitation of highly localized, spin-locked topological edge states at the interface.
• Demonstrated spin-momentum locking of the topological edge states.
• Confirmed consistency between real-space and reciprocal-space analyses.

Conclusions:

• The proposed cavity structure enables topological transitions and the generation of spin-locked edge states.
• Spatial control of infrared thermal radiation is achievable by leveraging phononic material properties.
• This work offers a strategy for tunable thermal emission in different spectral bands.