Anomalous Photon-Assisted Tunneling in Graphene

TL;DR

This paper explores how circularly polarized light influences electron tunneling in graphene, revealing anomalous photon-assisted transmission effects and modifications to Klein tunneling phenomena.

Contribution

It introduces the concept of anomalous photon-assisted tunneling in graphene and analyzes the impact of light-induced gaps on electron transmission properties.

Findings

Photon-assisted enhanced transmission predicted in graphene.

Suppression of perfect transmission in gapped dressed states.

Photon-induced gap reduces transmission in illuminated graphene.

Abstract

We investigated the Dirac electrons transmission through a potential barrier in the presence of circularly polarized light. An anomalous photon-assisted enhanced transmission is predicted and explained in a comparison with the well-known Klein paradox. It is demonstrated that the perfect transmission for nearly-head-on collision in an infinite graphene is suppressed in gapped dressed states of electrons, which is further accompanied by shift of peaks as a function of the incident angle away from the head-on collision. In addition, the perfect transmission in the absence of potential barrier is partially suppressed by a photon-induced gap in illuminated graphene. After the effect of rough edges of the potential barrier or impurity scattering is included, the perfect transmission with no potential barrier becomes completely suppressed and the energy range for the photon-assisted perfect transmission is reduced at the same time.