Dichotomy between large local and small ordered magnetic moment in Iron-based superconductors

TL;DR

This study uses LDA+DMFT to analyze iron-based superconductors, revealing a significant difference between local and ordered magnetic moments, and highlighting strong electronic correlations.

Contribution

The paper introduces a four-band LDA+DMFT model that captures magnetic properties more effectively than traditional five-band models, emphasizing the local-ordered moment dichotomy.

Findings

Reproduces results of models with explicit As p orbitals

Shows strong correlations beyond single-particle predictions

Identifies a dichotomy between local and ordered magnetic moments

Abstract

We study a four band model for iron-based superconductors within local density approximation + dynamical mean field theory (LDA+DMFT). This successfully reproduces the results of models which take As p degrees of freedom explicitly into account and has several physical advantages over the standard five d-band model. Our findings reveal that the new superconductors are more strongly correlated than their single-particle properties suggest. Two-particle correlation functions unveil the dichotomy between local and ordered magnetic moments in these systems, calling for further experiments to better resolve the short time scale spin dynamics.