Impact of Calcium on Transport Property of Graphene

TL;DR

This study investigates how calcium adsorbates affect graphene's transport properties, revealing discrepancies with existing theories and highlighting the need for improved experimental methods to better understand impurity scattering effects.

Contribution

It provides experimental data on calcium's impact on graphene conductivity, exposing gaps in current theoretical models and suggesting directions for future research.

Findings

Calcium causes linear dependence of conductivity on carrier density.

Experimental results diverge from existing theoretical predictions.

Current theories are inadequate to fully explain minimum conductivity in graphene.

Abstract

We have measured the impact of calcium adsorbates on the transport property of graphene. Although calcium renders conductivity linearly dependent on the carrier density of graphene as predicted, our experimental results diverge from the existing theoretical calculations. Our data expose the inadequacy of any existing theory to describe the minimum conductivity of graphene and indicate that a more complete testing of the impurity scattering calculations will require improving the experimental capabilities by minimizing the contribution from the substrate-bound charged impurities and developing an ability to count the number of adsorbates while measuring transport.