Mode mixing induced by disorder in graphene PNP junction in a magnetic field

TL;DR

This paper investigates how disorder-induced mode mixing affects electron transport in graphene PNP junctions under magnetic fields, revealing that disorder leads to uniform transmission properties and plays a crucial role in transport behavior.

Contribution

It demonstrates that disorder causes uniform mode mixing in graphene PNP junctions, significantly impacting electron transport properties and transmission fluctuations.

Findings

Disorder induces identical transmission and reflection matrix elements.

Mode mixing leads to uniform scattering states across incident modes.

Transmission fluctuations are suppressed in certain unipolar configurations.

Abstract

We study the electron transport through the graphene PNP junction under a magnetic field and show that modes mixing plays an essential role. By using the non-equilibrium Green's function method, the space distribution of the scattering state for a specific incident modes as well the elements of the transmission and reflection coefficient matrixes are investigated. All elements of the transmission (reflection) coefficient matrixes are very different for a perfect PNP junction, but they are same at a disordered junction due to the mode mixing. The space distribution of the scattering state for the different incident modes also exhibit the similar behaviors, that they distinctly differ from each other in the perfect junction but are almost same in the disordered junction. For a unipolar junction, when the mode number in the center region is less than that in the left and right regions, the fluctuations of the total transmission and reflection coefficients are zero, although each element has a large fluctuation. These results clearly indicate the occurrence of perfect mode mixing and it plays an essential role in a graphene PNP junction transport.