Probing of electromagnetic fields on atomic scale by photoelectric phenomena in graphene

TL;DR

This paper demonstrates a method to probe atomic-scale electromagnetic fields in graphene using infrared-induced photocurrents, revealing enhanced nonlinear optical phenomena due to substrate interactions.

Contribution

It introduces a novel noninvasive technique to measure electric fields at atomic distances in 2D materials via reststrahl band photocurrents.

Findings

Reststrahl band-assisted photocurrents observed in graphene.

Electric field probing at atomic surface distances.

Enhanced nonlinear optical effects in 2D structures.

Abstract

We report on the observation of the reststrahl band assisted photocurrents in epitaxial graphene on SiC excited by infrared radiation. The peculiar spectral dependence for frequencies lying within the reststrahl band of the SiC substrate provides a direct and noninvasive way to probe the electric field magnitude at atomic distances from the material's surface. Furthermore our results reveal that nonlinear optical and optoelectronic phenomena in 2D crystals and other atomic scale structures can be giantly enhanced by a proper combination of the spectral range and substrate material.