Strain-induced modifications of transport in gated graphene nanoribbons

TL;DR

This paper explores how various strains and edge disorders affect the electrical conductance of graphene nanoribbons, revealing complex resonance behaviors and the formation of pseudo-Landau levels under deformation.

Contribution

It provides a detailed analysis of strain and disorder effects on conductance, highlighting the role of pseudo-magnetic fields and resonance states in graphene nanoribbons.

Findings

Conductance initially decreases with homogeneous strain, then shows resonance structures, and is suppressed at high strain.

Edge disorder can restore conductance by inducing mode mixing.

Inhomogeneous deformations create pseudo-magnetic fields leading to additional resonance states and pseudo-Landau levels.

Abstract

We investigate the effects of homogeneous and inhomogeneous deformations and edge disorder on the conductance of gated graphene nanoribbons. Under increasing homogeneous strain the conductance of such devices initially decreases before it acquires a resonance structure, and finally becomes completely suppressed at larger strain. Edge disorder induces mode mixing in the contact regions, which can restore the conductance to its ballistic value. The valley-antisymmetric pseudo-magnetic field induced by inhomogeneous deformations leads to the formation of additional resonance states, which either originate from the coupling into Fabry-Perot states that extend through the system, or from the formation of states that are localized near the contacts, where the pseudo-magnetic field is largest. In particular, the n=0 pseudo-Landau level manifests itself via two groups of conductance resonances close to the charge neutrality point.