  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.
