Photonic emulation of two-dimensional materials with antiferromagnetic order

TL;DR

This paper presents a novel photonic metamaterial called spin-valley photonic topological insulator (SV-PTI) that emulates 2D materials with antiferromagnetic order, enabling control over topological states and energy compression.

Contribution

Introduction of SV-PTI as a new electromagnetic metamaterial that models antiferromagnetic 2D materials with tunable topological properties.

Findings

Single parameter controls chiral state propagation

Topological protection depends on line geometry

Energy compression achieved via group velocity control

Abstract

We introduce an electromagnetic metamaterial - a spin-valley photonic topological insulator (SV-PTI) - that emulates a wide class of theoretically predicted gapped two-dimensional materials with antiferromagnetic order coupled to the valley degree of freedom. First-principles electromagnetic simulations and an analytic model reveal that a single parameter controls the propagation properties of the chiral states at the domain wall between two SV-PTIs: their group velocity, polarization, and the existence/absence of topological protection. The latter is determined by the geometry of the line of the least frequency separation between the bandgap-forming propagation bands. Topologically-protected compression of electromagnetic energy via group velocity control is enabled by SV-PTIs.