Magneto-orbital coupling in iron pnictides

TL;DR

This paper introduces a magneto-orbital coupling mechanism to explain the weak energy gap at the Fermi level in the SDW state of iron pnictides, emphasizing the role of orbital mixing in gap formation.

Contribution

It proposes a novel magneto-orbital coupling mechanism that accounts for the weak energy gap in iron pnictides, highlighting the importance of orbital mixing terms.

Findings

Orbital mixing between $d_{xy}$ and $d_{xz}/d_{yz}$ is crucial for gap formation.

The mechanism reproduces the orbital composition of electron pockets.

The proposed coupling explains the weak energy gap observed in experiments.

Abstract

A magneto-orbital coupling mechanism is proposed to account for the weak energy gap at the Fermi energy in the $(\pi,0)$ ordered SDW state of a realistic three band model for iron pnictides involving $d_{xz}$, $d_{yz}$, and $d_{xy}$ Fe orbitals. The orbital mixing terms between the $d_{xy}$ and $d_{xz}/d_{yz}$ orbitals, which are important in reproducing the orbital composition of the elliptical electron pockets at $(\pm \pi,0)$ and $(0,\pm \pi)$, are shown to play a key role in the energy gap formation in the SDW state.