Ripples and Charge Puddles in Graphene on a Metallic Substrate

TL;DR

This paper investigates the relationship between charge puddles and ripples in graphene on a metallic substrate, revealing how decoupling restores intrinsic electronic properties and analyzing electron interference patterns.

Contribution

It demonstrates the coexistence and correlation of charge puddles and ripples, and shows that graphene can recover its intrinsic electronic properties when decoupled from the metal.

Findings

Charge puddles and ripples coexist and are correlated.

Graphene recovers its intrinsic electronic properties when decoupled from the substrate.

Linear dispersion relation indicates intrinsic behavior.

Abstract

Graphene on a dielectric substrate exhibits spatial doping inhomogeneities, forming electron-hole puddles. Understanding and controlling the latter is of crucial importance for unraveling many of graphene's fundamental properties at the Dirac point. Here we show the coexistence and correlation of charge puddles and topographic ripples in graphene decoupled from the metallic substrate it was grown on. The analysis of interferences of Dirac fermion-like electrons yields a linear dispersion relation, indicating that graphene on a metal can recover its intrinsic electronic properties.