Breakdown of the Law of Reflection at a Disordered Graphene Edge

TL;DR

This paper demonstrates that in disordered graphene edges, the traditional law of reflection breaks down, leading to diffusive electron reflection due to resonant scattering, which can be observed experimentally.

Contribution

It provides a theoretical and numerical analysis showing the breakdown of specular reflection in disordered graphene edges caused by resonant scattering.

Findings

Resonant scattering causes diffusive reflection in disordered graphene edges.

The diffusive reflection persists even when electron wavelength exceeds disorder correlation length.

Nonlocal conductance dips can be observed in magnetic focusing experiments.

Abstract

The law of reflection states that smooth surfaces reflect waves specularly, thereby acting as a mirror. This law is insensitive to disorder as long as its length scale is smaller than the wavelength. Monolayer graphene exhibits a linear dispersion at low energies and consequently a diverging Fermi wavelength. We present proof that for a disordered graphene boundary, resonant scattering off disordered edge modes results in diffusive electron reflection even when the electron wavelength is much longer than the disorder correlation length. Using numerical quantum transport simulations, we demonstrate that this phenomenon can be observed as a nonlocal conductance dip in a magnetic focusing experiment.