Spin-triplet p-wave pairing in a 3-orbital model for iron pnictide superconductors

TL;DR

This paper proposes that strong Hund's rule ferromagnetic interactions in a 3-orbital model can lead to spin-triplet p-wave superconductivity with nodal gaps in iron pnictide materials.

Contribution

It demonstrates that orbital hybridization and Hund's rule interactions can induce spin-triplet p-wave pairing in iron-based superconductors.

Findings

Spin-triplet p-wave pairing is favored under strong Hund's rule interactions.

The superconducting gap exhibits nodal lines on 3D Fermi surfaces.

Orbital hybridization is crucial for the pairing mechanism.

Abstract

We examine the possibility that the superconductivity in the newly discovered FeAs materials may be caused by the Coulomb interaction between d-electrons of the iron atoms. We find that when the Hund's rule ferromagnetic interaction is strong enough, the leading pairing instability is in spin-triplet p-wave channel in the weak coupling limit. The resulting superconducting gap has nodal lines on the 3D Fermi surfaces. The k dependent hybridization of several orbitals around a Fermi pocket is the key for the appearance of the spin-triplet p-wave pairing.