Tunable terahertz metamaterial absorber based on Dirac semimetal films

Area of Science:

• Condensed Matter Physics
• Materials Science
• Electromagnetics

Background:

• Metamaterial absorbers are crucial for terahertz (THz) applications.
• Conventional absorbers often lack dynamic tunability and require structural modification.
• 3D Dirac semimetal films (DSFs) offer unique electronic properties for novel device designs.

Purpose of the Study:

• To theoretically investigate tunable metamaterial absorbers utilizing 3D Dirac semimetal films in the THz regime.
• To design and analyze absorbers with various resonator shapes (square, circular, cross) for polarization-insensitive perfect absorption.
• To develop dual-band and broadband absorbers by combining different sized DSF resonators.

Main Methods:

• Theoretical analysis of metamaterial absorber properties.
• Numerical simulations to verify absorption performance.
• Investigation of dynamic tunability by altering Fermi energy.
• Comparison with conventional metal-based and graphene absorbers.

Main Results:

• Achieved perfect absorption for square, circular-patch, and cross-shaped resonators at normal incidence.
• Demonstrated polarization-insensitive absorption due to 90° rotational symmetry.
• Successfully designed dual-band and broadband absorbers by combining resonators of different sizes.
• Showcased dynamic tunability of absorption by adjusting Fermi energy, unlike static metal absorbers.

Conclusions:

• DSF-based metamaterial absorbers offer a promising route for tunable THz applications.
• The dynamic tunability via Fermi energy presents an advantage over traditional fabrication-dependent methods.
• DSFs act as efficient "Salisbury screens" for THz absorption, offering convenience over graphene.