Triplet $p$-wave pairing correlation in low doped zigzag graphene nanoribbons

TL;DR

This paper demonstrates the emergence of edge spin triplet p-wave superconducting pairing in slightly doped zigzag graphene nanoribbons, driven by ferromagnetic fluctuations and electron-electron correlations, with a doping-dependent phase diagram similar to high-temperature superconductors.

Contribution

It introduces a comprehensive computational study showing p-wave pairing mediated by ferromagnetic edge fluctuations in doped zigzag graphene nanoribbons, highlighting the role of electron correlations.

Findings

Edge spin-triplet p-wave pairing is mediated by ferromagnetic fluctuations.

Spin susceptibility and pairing interactions increase with Coulomb interaction.

Doping affects the pairing correlation and edge spin correlations similarly to high-Tc superconductors.

Abstract

We reveal an edge spin triplet $p-$wave superconducting pairing correlation in slightly doped zigzag graphene nanoribbons. By employing a method that combines random-phase approximation, the finite-temperature determinant quantum Monte Carlo approach, and the ground-state constrained-path quantum Monte Carlo method, it is shown that such a spin-triplet pairing is mediated by the ferromagnetic fluctuations caused by the flat band at the edge. The spin susceptibility and effective pairing interactions at the edge strongly increase as the on-site Coulomb interaction increases, indicating the importance of electron-electron correlations. It is also found that the doping-dependent ground-state $p$-wave pairing correlation bears some similarity to the famous superconducting dome in the phase diagram of a high-temperature superconductor, while the spin correlation at the edge is weakened as the system is doped away from half filling.