Conductance of bilayer graphene in the presence of a magnetic field: Effects of disorder

TL;DR

This paper studies how disorder affects the electronic conductance and quantum Hall effects in bilayer graphene nanoribbons under magnetic fields, revealing robustness of certain conductance features and disorder-induced conductance enhancement.

Contribution

It provides a detailed analysis of disorder effects on conductance quantization and Hall plateaus in bilayer graphene with magnetic fields using Green's function methods.

Findings

Lowest Hall plateau remains stable despite disorder.

Asymmetry destroys conductance quantization and Hall plateaus.

Disorder enhances conductance in n-p regions under magnetic fields.

Abstract

We investigate the electronic transport properties of unbiased and biased bilayer graphene nanoribbon in n-p and n-n junctions subject to a perpendicular magnetic field. Using the non-equilibrium Green's function method and the Landauer-B\"{u}ttiker formalism, the conductance is studied for the cases of clean, on-site, and edge disordered bilayer graphene. We show that the lowest Hall plateau remains unchanged in the presence of disorder, whereas asymmetry destroys both the plateaus and conductance quantization. In addition, we show that disorder induces an enhancement of the conductance in the n-p region in the presence of magnetic fields. Finally, we show that the equilibration of quantum Hall edge states between distinctively doped regions causes Hall plateaus to appear in the regime of complete mode mixing.