Spin-orbit coupling in Fe-based superconductors

TL;DR

This paper investigates how spin-orbit coupling influences the spin resonance in iron-based superconductors, revealing its role in breaking spin-rotational symmetry and affecting experimental observations.

Contribution

It introduces a multiorbital model incorporating spin-orbit interaction to explain the observed spin resonance features in Fe-based superconductors.

Findings

Spin-orbit coupling affects the dynamical spin susceptibility.

It explains the disparity between longitudinal and transverse components.

The model aligns with neutron scattering experimental results.

Abstract

We study the spin resonance peak in recently discovered iron-based superconductors. The resonance peak observed in inelastic neutron scattering experiments agrees well with predicted results for the extended $s$-wave ($s_\pm$) gap symmetry. Recent neutron scattering measurements show that there is a disparity between longitudinal and transverse components of the dynamical spin susceptibility. Such breaking of the spin-rotational invariance in the spin-liquid phase can occur due to spin-orbit coupling. We study the role of the spin-orbit interaction in the multiorbital model for Fe-pnictides and show how it affects the spin resonance feature.