Klein Backscattering and Fabry-Perot Interference in Graphene Heterojunctions

TL;DR

This paper develops a theoretical model for quantum-coherent transport in graphene p-n-p structures, revealing how Klein scattering influences interference patterns and can be detected via magnetic field-induced phase shifts.

Contribution

It introduces a comprehensive theory accounting for Klein backscattering effects on Fabry-Perot interference in graphene heterojunctions, highlighting observable magnetic field signatures.

Findings

Klein phenomenon causes a phase shift in interference fringes.

Weak magnetic fields induce a half-period shift in Fabry-Perot patterns.

The effect persists despite moderate potential inhomogeneity.

Abstract

We present a theory of quantum-coherent transport through a lateral p-n-p structure in graphene, which fully accounts for the interference of forward and backward scattering on the p-n interfaces. The backreflection amplitude changes sign at zero incidence angle because of the Klein phenomenon, adding a phase $\pi$ to the interference fringes. The contributions of the two p-n interfaces to the phase of the interference cancel with each other at zero magnetic field, but become imbalanced at a finite field. The resulting half a period shift in the Fabry-Perot fringe pattern, induced by a relatively weak magnetic field, can provide a clear signature of Klein scattering in graphene. This effect is shown to be robust in the presence of spatially inhomogeneous potential of moderate strength.