Charge confinement and Klein tunneling from doping graphene

TL;DR

This paper explores how defects and structural modifications in graphene influence its electronic transport, revealing mechanisms for charge confinement and conditions under which Klein tunneling occurs.

Contribution

It demonstrates that breaking sublattice symmetry induces charge confinement, and analyzes how tensor barriers affect intervalley mixing and Klein tunneling in graphene.

Findings

Breaking sublattice symmetry leads to confined states of Dirac fermions.

Tensor barriers cause intervalley mixing and enable Klein tunneling.

Structural defects can significantly alter graphene's transport properties.

Abstract

In the present work, we investigate how structural defects in graphene can change its transport properties. In particular, we show that breaking of the sublattice symmetry in a graphene monolayer overcomes the Klein effect, leading to confined states of massless Dirac fermions. Experimentally, this corresponds to chemical bonding of foreign atoms to carbon atoms, which attach themselves to preferential positions on one of the two sublattices. In addition, we consider the scattering off a tensor barrier, which describes the rotation of the honeycomb cells of a given region around an axis perpendicular to the graphene layer. We demonstrate that in this case the intervalley mixing between the Dirac points emerges, and that Klein tunneling occurs.