Weak Localisation in Clean and Highly Disordered Graphene

TL;DR

This study investigates the weak localisation effect in graphene with varying mobilities, revealing universal properties of localisation length and phase coherence length through experimental analysis.

Contribution

It introduces a method to extract localisation and phase coherence lengths in graphene regardless of mobility, highlighting universal weak localisation behavior.

Findings

Localization length shows universal weak localisation dependence.

High mobility samples have sharp weak localisation peaks.

Low mobility samples exhibit broad peaks at low temperatures.

Abstract

We look at the magnetic field induced weak localisation peak of graphene samples with different mobilities. At very low temperatures, low mobility samples exhibit a very broad peak as a function of the magnetic field, in contrast to higher mobility samples, where the weak localisation peak is very sharp. We analyze the experimental data in the context of the localisation length, which allows us to extract, both the localisation length and the phase coherence length of the samples, regardless of their mobilities. This analysis is made possible by the observation that the localisation length undergoes a generic weak localisation dependence with striking universal properties.