Current-induced birefringent absorption and non-reciprocal plasmons in graphene

TL;DR

This paper investigates how a direct current in graphene influences its optical and plasmonic properties, revealing birefringent absorption and non-reciprocal, tunable plasmons, with potential experimental implications.

Contribution

It provides analytical and numerical analysis of current-induced birefringence and non-reciprocity in graphene's optical response and plasmons, a novel insight into current-controlled plasmonics.

Findings

Current modifies Pauli blocking and induces birefringent absorption.

Graphene plasmons exhibit non-reciprocity and collimation tunable by current.

Potential for experimental measurement of these effects.

Abstract

We present extensive calculations of the optical and plasmonic properties of a graphene sheet carrying a dc current. By calculating analytically the density-density response function of current-carrying states at finite temperature, we demonstrate that an applied dc current modifies the Pauli blocking mechanism and that absorption acquires a birefringent character with respect to the angle between the in-plane light polarization and current flow. Employing the random phase approximation at finite temperature, we show that graphene plasmons display a degree of non-reciprocity and collimation that can be tuned with the applied current. We discuss the possibility to measure these effects.