Modeling Antiferromagnetic Phase in Iron Pnictides: Weakly Ordered State

TL;DR

This paper models the antiferromagnetic phase in iron pnictides using a five-band mean-field approach, reproducing experimental excitation spectra and predicting characteristic magnetoresistance behavior.

Contribution

It introduces a five-band model with small magnetic moments that aligns with experimental optical spectra and provides predictions for interlayer magnetoresistance in iron pnictides.

Findings

Reproduces multi-peak optical excitation spectra below Néel temperature

Predicts temperature-independent high-energy spectral features

Forecasts characteristic field dependence of magnetoresistance

Abstract

We examine electronic states of antiferromagnetic phase in iron pnictides by mean-field calculations of the optical conductivity. We find that a five-band model exhibiting a small magnetic moment, inconsistent with the first-principles calculations, reproduces well the excitation spectra characterized by a multi-peak structure emerging below the N\'{e}el temperature at low energy, together with an almost temperature-independent structure at high energy. Investigating the interlayer magnetoresistance for this model, we also predict its characteristic field dependence reflecting the Fermi surface.