Correlation between resistance fluctuations and temperature dependence of conductivity in graphene

TL;DR

This paper explores how resistance fluctuations in graphene relate to temperature-dependent conductivity, revealing that electron wave interference significantly influences resistance changes at low temperatures.

Contribution

It introduces a detailed analysis linking resistance fluctuations to temperature dependence in graphene, supported by experimental verification and simple modeling expressions.

Findings

Resistance fluctuations are correlated with temperature-dependent conductivity.

Electron wave interference causes resistance changes at low temperatures.

The proposed models fit experimental data across different charge densities.

Abstract

The weak temperature dependence of the resistance R(T) of monolayer graphene1-3 indicates an extraordinarily high intrinsic mobility of the charge carriers. Important complications are the presence of mobile scattering centres that strongly modify charge transport, and the presence of strong mesoscopic conductance fluctuations that, in graphene, persist to relatively high temperatures4,5. In this Letter, we investigate the surprisingly varied changes in resistance that we find in graphene flakes as temperature is lowered below 70 K. We propose that these changes in R(T) arise from the temperature dependence of the scattered electron wave interference that causes the resistance fluctuations. Using the field effect transistor configuration, we verify this explanation in detail from measurements of R(T) by tuning to different gate voltages corresponding to particular features of the resistance fluctuations. We propose simple expressions that model R(T) at both low and high charge carrier densities.