Collective cyclotron motion of the relativistic plasma in graphene

TL;DR

This paper develops a theory for the thermo-electric response of graphene's relativistic electron plasma, revealing a temperature-dependent collective cyclotron motion with damping, detectable via microwave experiments.

Contribution

It introduces a novel hydrodynamic model for graphene's plasma, predicting a finite damping of cyclotron motion due to electron-hole collisions, unlike traditional systems.

Findings

Relativistic cyclotron frequency depends on temperature and charge density.

Finite damping of cyclotron resonance due to collisions.

Predicted strong Nernst effect in graphene.

Abstract

We present a theory of the finite temperature thermo-electric response functions of graphene, in the hydrodynamic regime induced by electron-electron collisions. In moderate magnetic fields, the Dirac particles undergo a collective cyclotron motion with a temperature-dependent relativistic cyclotron frequency proportional to the net charge density of the Dirac plasma. In contrast to the undamped cyclotron pole in Galilean-invariant systems (Kohn's theorem), here there is a finite damping induced by collisions between the counter-propagating particles and holes. This cyclotron motion shows up as a damped pole in the frequency dependent conductivities, and should be readily detectable in microwave measurements at room temperature. We also discuss the large Nernst effect to be expected in graphene.