Transmission in graphene through tilted barrier in laser field

TL;DR

This paper investigates how a laser field influences electron transmission in graphene with a tilted barrier, revealing that laser parameters significantly affect transmission probabilities and the Klein effect persists.

Contribution

It introduces a Floquet theory-based approach to analyze Dirac fermion transmission in graphene under laser illumination with a tilted barrier, highlighting the laser's impact on transmission behavior.

Findings

Laser field strongly affects transmission probabilities.

Klein effect remains present despite laser influence.

Transmission across all bands is effectively suppressed.

Abstract

We study the transmission of Dirac fermions in graphene through a tilted barrier potential in the presence of a laser field of frequency $\omega$. By using Floquet theory, we solve the Dirac equation and then obtain the energy spectrum. The boundary conditions together with the transfer matrix method allow us to determine the transmission probabilities corresponding to all energy bands $E+l\hbar\omega$ $(l=0,\pm1, \cdots)$. By limiting to the central band $l=0$ and the two first side bands $l=\pm 1$, we show that the transmissions are strongly affected by the laser field and barrier. Indeed, it is found that the Klein effect is still present, a variety of oscillations are inside the barrier, and there is essentially no transmission across all bands.