Photonic Altermagnets: Magnetic Symmetries in Photonic Structures

TL;DR

This paper demonstrates that photonic crystals can mimic altermagnetism, enabling spin-split photonic bands and polarization control, which opens new avenues for optical spintronics without relying on spin-orbit interactions.

Contribution

It introduces a photonic analogue of altermagnetism in engineered photonic crystals, showcasing spin-split bands and polarization-based light control as a novel platform.

Findings

Photonic crystals can host spin space group symmetries.

Spin-split bands enable circularly polarized light isolation.

Platform for testing spin-split band properties in photonics.

Abstract

The unique physical properties of altermagnets, when transplanted to photonic systems, are anticipated to offer a new degree of freedom for engineering electromagnetic waves. Here, we show that a photonic analogue of altermagnetism can be mimicked in photonic crystals, where engineered photonic crystals can host spin space group symmetries. Our approach allows for the creation of spin-split bands and the corresponding transport properties provide an effective platform for circularly polarized light isolation without the need of geometrodynamic spin-orbit interaction. Beyond the concurrent solid-state materials, we anticipate our work to offer photonic crystals as a versatile platform to test the spin-split band properties and inspire optical designs for photospintronic applications.