Magneto-transport in Disordered Graphene: from Weak Localization to Strong Localization

TL;DR

This study investigates how mild disorder affects magneto-transport in graphene, revealing a transition from weak to strong localization influenced by phase coherence and electron-electron interactions.

Contribution

It demonstrates the continuous tuning of graphene's transport regime from weak to strong localization through disorder, gate voltage, and temperature variations.

Findings

Conductivity decreases by over 1000 times from 100K to 1K in ozone-exposed graphene.

Transition from weak to strong localization occurs when phase coherence length matches localization length.

Disorder-enhanced electron-electron interactions significantly impact resistivity.

Abstract

We present a magneto-transport study of graphene samples into which a mild disorder was introduced by exposure to ozone. Unlike the conductivity of pristine graphene, the conductivity of graphene samples exposed to ozone becomes very sensitive to temperature: it decreases by more than 3 orders of magnitude between 100K and 1K. By varying either an external gate voltage or temperature, we continuously tune the transport properties from the weak to the strong localization regime. We show that the transition occurs as the phase coherence length becomes comparable to the localization length. We also highlight the important role of disorder-enhanced electron-electron interaction on the resistivity.