Strain Effect on Transmission in Graphene Laser Barrier

TL;DR

This paper explores how strain along different directions affects electron tunneling in a graphene laser barrier, revealing directional dependence, oscillatory behavior, and resonance phenomena in transmission properties.

Contribution

It provides a detailed analysis of strain effects on Dirac fermion tunneling in graphene barriers using Floquet theory, highlighting directional and amplitude-dependent transmission features.

Findings

Transmission decreases with smaller barrier width in the unstrained case.

Strain reduces the number of oscillations in transmission channels.

Fano resonances appear with changes in laser amplitude and frequency.

Abstract

We investigate the strain effect along armchair and zigzag directions on the tunneling transport of Dirac fermions in graphene laser barrier through a time dependent potential along y-axis. Our system is composed of three regions and the central one is subjected to a deformation of strength S. Based on Dirac equation and the Floquet approach, we determine the eigenvalues and eigenspinors for each region. Using the boundary conditions at interfaces together with the transfer matrix method we identify the transmission in the different Floquet sideband states as function of the physical parameters. In the strainless case, we show that the transmisson of central band decreases for smaller values of the barrier width and rapidly oscillates with different amplitude for larger ones. Whereas the transmission for the first sidebands increases from zero and shows a damped oscillatory profile. It is found that the number of oscillations in all transmission channels reduces with increasing the strength of armchair strain but becomes more important by switching the deformation to zigzag. Moreover, it is observed the appearance of Fano type resonance peaks by altering the amplitude and the frequency of the laser field.