Edge currents driven by terahertz radiation in graphene in quantum Hall regime

TL;DR

This paper reports the observation of terahertz radiation-induced edge currents in graphene under quantum Hall conditions, driven by non-equilibrium effects in chiral edge channels, supported by a developed microscopic theory.

Contribution

It introduces a new understanding of how polarized terahertz radiation induces edge currents in graphene within the quantum Hall regime, supported by experimental and theoretical analysis.

Findings

Edge photocurrent depends on magnetic field polarity.

Photocurrent magnitude varies with radiation polarization.

The developed theory matches experimental data.

Abstract

We observe that the illumination of unbiased graphene in the quantum Hall regime with polarized terahertz laser radiation results in a direct edge current. This photocurrent is caused by an imbalance of persistent edge currents, which are driven out of thermal equilibrium by indirect transitions within the chiral edge channel. The direction of the edge photocurrent is determined by the polarity of the external magnetic field, while its magnitude depends on the radiation polarization. The microscopic theory developed in this paper describes well the experimental data.