Functional renormalization group and variational Monte Carlo studies of the electronic instabilities in graphene near 1/4 doping

TL;DR

This study investigates electronic instabilities in near 1/4 doped graphene using advanced computational methods, revealing potential for Chern insulators and superconductivity near this doping level.

Contribution

It introduces a modified FRG approach for better treatment of the van Hove singularity and identifies the dominant electronic phases near 1/4 doping in graphene.

Findings

At 1/4 doping, a chiral spin density wave state with quantized Hall effect is observed.

Deviations from 1/4 doping favor $d_{x^2-y^2}+i d_{xy}$ Cooper pairing.

Graphene near 1/4 doping is promising for realizing Chern insulators and superconductors.

Abstract

We study the electronic instabilities of near 1/4 electron doped graphene using the functional renormalization group (FRG) and variational Monte-Carlo method. A modified FRG implementation is utilized to improve the treatment of the von Hove singularity. At 1/4 doping the system is a chiral spin density wave state exhibiting the anomalous quantized Hall effect, or equivalently a Chern insulator. When the doping deviates from 1/4, the $d_{x^2-y^2}+i d_{xy}$ Cooper pairing becomes the leading instability. Our results suggest near 1/4 electron or hole doped graphene is a fertile playground for the search of Chern insulators and superconductors.