Pairing Symmetry and Pairing State in Ferropnictides: Theoretical Overview

TL;DR

This paper reviews the theoretical basis and experimental evidence for the unconventional s+/- pairing state in ferropnictides, emphasizing interband pairing driven by magnetic fluctuations.

Contribution

It provides a comprehensive overview of the electronic structure, magnetic excitations, and experimental data supporting the s+/- pairing state in ferropnictides.

Findings

s+/- state is a likely pairing candidate in ferropnictides

Magnetic fluctuations play a key role in interband pairing

Experimental evidence both supports and challenges the s+/- pairing hypothesis

Abstract

We review the main ingredients for an unconventional pairing state in the ferropnictides, with particular emphasis on interband pairing due to magnetic fluctuations. Summarizing the key experimental prerequisites for such pairing, the electronic structure and nature of magnetic excitations, we discuss the properties of the s+/- state that emerges as a likely candidate pairing state for these materials and survey experimental evidence in favor of and against this novel state of matter.