A Hybrid-Monte-Carlo study of monolayer graphene with partially screened Coulomb interactions at finite spin density

Understand

We report on Hybrid-Monte-Carlo simulations at finite spin density of the $\pi$-band electrons in monolayer graphene with realistic inter-electron interactions.

• Unlike simulations at finite charge-carrier density, these are not affected by a fermion-sign problem.
• Our results are in qualitative agreement with an interaction-induced warping of the Fermi contours, and a reduction of the bandwidth as observed in angle resolved photoemission spectroscopy experiments on charge-doped graphene systems.
• Furthermore, we find evidence that the neck-disrupting Lifshitz transition, which occurs when the Fermi level traverses the van Hove singularity (VHS), becomes a true quantum phase transition due to interactions.