Correlation-Driven Electron-Hole Asymmetry in Graphene Field Effect Devices

TL;DR

This paper demonstrates that electronic correlations intrinsically cause electron-hole asymmetry in graphene, revealed through direct quasiparticle self-energy measurements, offering new insights into asymmetries in correlated materials.

Contribution

It introduces a new method to measure quasiparticle self-energy in graphene devices, revealing the role of correlations in electron-hole asymmetry.

Findings

Correlation strength increases from hole to electron doping

Band velocity increases with doping

Inverse quasiparticle lifetime decreases with doping

Abstract

Electron-hole asymmetry is a fundamental property in solids that can determine the nature of quantum phase transitions and the regime of operation for devices. The observation of electron-hole asymmetry in graphene and recently in the phase diagram of bilayer graphene has spurred interest into whether it stems from disorder or from fundamental interactions such as correlations. Here, we report an effective new way to access electron-hole asymmetry in 2D materials by directly measuring the quasiparticle self-energy in graphene/Boron Nitride field effect devices. As the chemical potential moves from the hole to the electron doped side, we see an increased strength of electronic correlations manifested by an increase in the band velocity and inverse quasiparticle lifetime. These results suggest that electronic correlations play an intrinsic role in driving electron hole asymmetry in graphene and provide a new insight for asymmetries in more strongly correlated materials.