On the coexistence of antiferromagnetism and d + i d superconducting correlations in the graphene bilayer

TL;DR

This paper explores how antiferromagnetism and d + i d superconducting correlations can coexist in a graphene bilayer, providing insights into experimental observations of magnetic field effects on the material.

Contribution

It demonstrates that a t-J-U model on a honeycomb monolayer can describe the coexistence of antiferromagnetism and d + i d superconductivity in graphene bilayers.

Findings

Coexistence of antiferromagnetism and superconducting correlations shown.

Quadratic magnetic field dependence of the gap matches experiments.

Model relevance confirmed for graphene bilayer physics.

Abstract

We discuss t-J-U model on a honeycomb monolayer that has the same low-energy description of the kinetic term as graphene bilayer, and in particular study coexistence of antiferromagnetism and superconducting correlations that originate from Cooper pairs without phase coherence. We show that the model is relevant for the description of graphene bilayer and that the presence of the d + i d superconducting correlations with antiferromagnetism can lead to quadratic dependence in small magnetic fields of the gap of the effective monolayer consistent with the transport measurements of Velasco et al. on the graphene bilayer.