Pairing mechanism in Fe pnictide superconductors

TL;DR

This paper demonstrates that in Fe pnictide superconductors, an attractive spin-mediated pairing interaction arises from a unitary transformation of a two-band Hamiltonian, suggesting a singlet superconducting order parameter.

Contribution

The study introduces a novel theoretical approach showing how large pnictogen polarizabilities lead to an attractive pairing interaction in Fe pnictides.

Findings

Attractive spin-mediated Hubbard term in $d_{xz}$, $d_{yz}$ channels

Implication of singlet superconducting order parameter

Role of pnictogen polarizabilities in pairing mechanism

Abstract

By applying an exact unitary transformation to a two-band hamiltonian which also includes the effects due to large pnictogen polarizabilities, we show that an attractive spin-mediated Hubbard term appears in the $d_{xz}$, $d_{yz}$ nearest-neighbour channel. This pairing mechanism implies a singlet superconducting order parameter in iron pnictides.