Theory of resonant photon drag in monolayer graphene

TL;DR

This paper develops a theoretical framework for understanding resonant photon drag effects in monolayer graphene, highlighting how electron current depends on photon frequency, polarization, and the mechanisms of non-resonant and resonant drag effects.

Contribution

The paper introduces a detailed theory of resonant photon drag in graphene, distinguishing between non-resonant and resonant effects and analyzing their dependence on photon frequency and polarization.

Findings

Resonant drag effect (RDE) occurs near specific photon frequencies.

The drag current depends on radiation polarization and can be perpendicular to photon momentum.

RDE exists in a narrow frequency region close to the interband transition threshold.

Abstract

Photon drag current in monolayer graphene with degenerate electron gas is studied under interband excitation near the threshold of fundamental transitions. Two main mechanisms generate an emergence of electron current. Non-resonant drag effect (NDE) results from direct transfer of in-plane photon momentum ${\bf q}$ to electron and dependence of matrix elements of transitions on ${\bf q}$. Resonant drag effect (RDE) originates from ${\bf q}$-dependent selection of transitions due to a sharp form of the Fermi distribution in energy. The drag current essentially depends on the polarization of radiation and, in general, is not parallel to ${\bf q}$. The perpendicular current component appears if the in-plain electric field is tilted towards ${\bf q}$. The RDE has no smallness connected with $q$ and exists in a narrow region of photon frequency $\omega$: $|\hbar\omega-2\epsilon_F|< \hbar sq$, where $s$ is the electron velocity.