Chiral $p$-wave superconductivity in twisted bilayer graphene from dynamical mean field theory

TL;DR

This study uses cluster dynamical mean field theory to demonstrate that twisted bilayer graphene can host chiral p-wave superconductivity near certain electron fillings, aligning with experimental observations.

Contribution

It applies CDMFT to a Hubbard model of twisted bilayer graphene, revealing the stabilization of chiral p-wave superconductivity with a detailed theoretical approach.

Findings

Triplet p+ip superconductivity is stabilized by CDMFT.

A subdominant singlet d+id state is also present.

Superconducting order parameter peaks near quarter- and three-quarter fillings.

Abstract

We apply cluster dynamical mean field theory with an exact-diagonalization impurity solver to a Hubbard model for magic-angle twisted bilayer graphene, built on the tight-binding model proposed by Kang and Vafek (2018), which applies to the magic angle $1.30^\circ$. We find that triplet superconductivity with $p+ip$ symmetry is stabilized by CDMFT, as well as a subdominant singlet $d+id$ state. A minimum of the order parameter exists close to quarter-filling and three-quarter filling, as observed in experiments.