Transport through graphene nanoribbons: suppression of transverse quantization by symmetry breaking

TL;DR

This paper studies how disorder affects electron transport in graphene nanoribbons, showing that symmetry breaking suppresses size quantization patterns and explaining experimental observations.

Contribution

It demonstrates that symmetry breaking disorder destroys transverse quantization in graphene nanoribbons, providing a theoretical explanation for experimental results.

Findings

Size quantization appears only with preserved SU(2) pseudospin symmetry.

Symmetry breaking disorder suppresses observable transverse quantization.

Monte-Carlo simulations replicate quantum-mechanical features of transport.

Abstract

We investigate transport through nanoribbons in the presence of disorder scattering. We show that size quantization patterns are only present when SU(2) pseudospin symmetry is preserved. Symmetry breaking disorder renders transverse quantization invisible, which may provide an explanation for the necessity of suspending graphene nanoconstrictions to obtain size quantization signatures in very recent experiments. Employing a quasi-classical Monte-Carlo simulation, we are able to reproduce and explain key qualitative features of the full quantum-mechanical calculations.