Suppression of conductance fluctuation in weakly disordered mesoscopic graphene samples near the charge neutral point

TL;DR

This study investigates conductance fluctuations in weakly disordered graphene devices, revealing a rapid suppression near the charge neutral point, which enhances understanding of quantum transport in graphene.

Contribution

It demonstrates the suppression of conductance fluctuations in graphene near the charge neutral point using a novel fabrication method and discusses potential physical mechanisms.

Findings

Conductance fluctuations are reproducible and tunable.

Fluctuation amplitude decreases sharply near the charge neutral point.

Suppression occurs within the weakly disordered regime.

Abstract

We measured the conductance fluctuation of bi- and trilayer graphene devices prepared on mechanical exfoliated graphene by an all-dry, lithography-free process using an ultrathin quartz filament as a shadow mask. Reproducible fluctuations in conductance as a function of applied gate voltage or magnetic field were found. As the gate voltage was tuned so that the graphene device was pushed to the charge neutral point, the amplitude of the conductance fluctuation was found to be suppressed quickly from a value consistent with universal conductance fluctuation when the devices were still well within weakly disordered regime. The possible physical origins of the suppression are discussed.