Correlation-induced triplet pairing superconductivity in graphene-based moir\'e systems

TL;DR

This paper explores the emergence of triplet superconductivity in graphene-based moiré systems, highlighting an $f$-wave pairing mechanism driven by correlation effects and valley-sublattice structure, with potential magnetic field effects.

Contribution

It introduces a correlation-induced spin-fermion model on a honeycomb lattice that predicts $f$-wave triplet pairing in graphene moiré systems, a novel mechanism distinct from known triplet superconductors.

Findings

$f$-wave pairing is favored due to valley-sublattice structure

Superconducting state is time-reversal symmetric and fully gapped

Small in-plane magnetic field can enhance transition temperature

Abstract

Motivated by the possible non-spin-singlet superconductivity in the magic-angle twisted trilayer graphene experiment, we investigate the triplet-pairing superconductivity arising from a correlation-induced spin-fermion model on a honeycomb lattice. We find that the $f$-wave pairing is favored due to the valley-sublattice structure, and the superconducting state is time-reversal symmetric, fully gapped, and non-topological. With a small in-plane magnetic field, the superconducting state becomes partially polarized, and the transition temperature can be slightly enhanced. Our results apply qualitatively for the triplet-pairing superconductivity in graphene-based moir\'e systems, which is fundamentally distinct from triplet superconductivity in $^3$He and ferromagnetic superconductors.