Positive-Negative Birefringence in Multiferroic Layered Metasurfaces.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Electromagnetism

Background:

• Multiferroic materials offer unique magnetoelectric coupling properties.
• Metamaterials enable exotic electromagnetic wave interactions, including negative refraction.
• Controlling light propagation with external fields is a key research goal.

Purpose of the Study:

• To identify the operating regime for magnetically and ferroelectrically controllable negative refraction.
• To investigate light propagation in a multiferroic, oxide-based nanoscopic layered metastructure.
• To explore novel optical phenomena arising from magnetoelectric control of light.

Main Methods:

• Analytical and numerical simulations based on discretized, coupled Maxwell/ferroelectric/ferromagnetic dynamics.
• Derivation of a biquadratic relation for the refractive index.
• Quantification of ordinary and negative refraction scenarios using analytical formulas and full numerical simulations.

Main Results:

• Identified the regime for controllable negative refraction in a strontium titanate (SrTiO3) and yttrium iron garnet (Y3Fe2(FeO4)3, YIG) layered metastructure.
• Confirmed analytical formulas for refractive index with numerical simulations, accurately predicting wave propagation.
• Discovered phenomena at GHz frequencies, including positive-negative birefringence and magnetically controlled light trapping and acceleration, due to polarization-dependent refractive indices.

Conclusions:

• The study establishes a framework for achieving tunable negative refraction in multiferroic heterostructures.
• Demonstrated the potential for novel optical effects and precise light manipulation using magnetoelectric control.
• Opens avenues for advanced photonic devices operating in the GHz frequency range.