# Infrared Topological Plasmons in Graphene

## TL;DR

This paper introduces a graphene-based plasmonic system with topologically protected one-way edge states at infrared frequencies, enabling robust, defect-immune plasmonic devices through engineered band topology and magnetic field effects.

## Contribution

It presents a novel design of periodically patterned graphene supporting topological edge states at infrared frequencies, demonstrating a practical high-frequency topological plasmonic platform.

## Key findings

- Supports topologically nontrivial bandgaps up to tens of terahertz
- Hosts topologically protected one-way edge plasmons
- Edge states are immune to backscattering from defects

## Abstract

We propose a two-dimensional plasmonic platform - periodically patterned monolayer graphene - which hosts topological one-way edge states operable up to infrared frequencies. We classify the band topology of this plasmonic system under time-reversal-symmetry breaking induced by a static magnetic field. At finite doping, the system supports topologically nontrivial bandgaps with mid-gap frequencies up to tens of terahertz. By the bulk-edge correspondence, these bandgaps host topologically protected one-way edge plasmons, which are immune to backscattering from structural defects and subject only to intrinsic material and radiation loss. Our findings reveal a promising approach to engineer topologically robust chiral plasmonic devices and demonstrate a realistic example of high-frequency topological edge state.