Electric field-induced chiral d+id superconducting state in AA-stacked bilayer graphene: A quantum Monte Carlo study

TL;DR

This study uses quantum Monte Carlo simulations to show that applying an electric field to AA-stacked bilayer graphene induces a chiral d+id superconducting state, with enhanced pairing correlations linked to increased density of states.

Contribution

First systematic quantum Monte Carlo investigation revealing electric field-induced chiral d+id superconductivity in AA-stacked bilayer graphene.

Findings

Electric field induces chiral d+id pairing in AA-stacked graphene.

Pairing correlation increases with Coulomb interaction strength.

Electric field suppresses antiferromagnetic spin correlations.

Abstract

Using constrained-path quantum Monte Carlo method, we systematically study the Hubbard model on AA-stacked honeycomb lattices with electric field. Our simulation demonstrates a dominant chiral d+id wave pairing induced by the electric field at half filling. In particular, as the on-site Coulomb interaction increases, the effective pairing correlation of chiral d+id superconducting state exhibits increasing behavior. We attribute the electric field induced d+id superconductivity to an increased density of states near the Fermi energy and an suppressed antiferromagnetic spin correlation after turning on the electric field. Our results strongly suggest the AA-stacked graphene system with electric field is a good candidate for chiral d+id superconductors.