Chiral plasmon in gapped Dirac systems

TL;DR

This paper investigates how circularly polarized light induces valley imbalance and Berry curvature in gapped Dirac materials, leading to chiral edge modes, waveguiding, and polarization effects.

Contribution

It introduces the concept of chiral plasmon modes in gapped Dirac systems under optical pumping, highlighting their nonreciprocal and waveguiding properties.

Findings

Valley imbalance causes finite transverse conductivity.

Chiral edge modes emerge in pumped gapped Dirac materials.

Giant polarization rotation observed in nanoribbon arrays.

Abstract

We study the electromagnetic response and surface electromagnetic modes in a generic gapped Dirac material under pumping with circularly polarized light. The valley imbalance due to pumping leads to a net Berry curvature, giving rise to a finite transverse conductivity. We discuss the appearance of nonreciprocal chiral edge modes, their hybridization and waveguiding in a nanoribbon geometry, and giant polarization rotation in nanoribbon arrays.