Effect of the tetrahedral distortion on the electronic properties of iron-pnictides

TL;DR

This study investigates how tetrahedral distortions influence the electronic structure of iron pnictides, revealing strong sensitivity especially in a two-orbital model, with implications for understanding their electronic behavior.

Contribution

The paper introduces a tight binding model that captures the impact of tetrahedral distortion on the electronic properties of iron pnictides, highlighting the importance of orbital considerations.

Findings

Density of states and band structure are highly sensitive to tetrahedral distortion.

A flat band around the Fermi level forms in a two-orbital model due to distortion.

Including the d_xy orbital alters the flat band but maintains angle dependence.

Abstract

We study the dependence of the electronic structure of iron pnictides on the angle formed by the arsenic-iron bonds. Within a Slater-Koster tight binding model which captures the correct symmetry properties of the bands, we show that the density of states and the band structure are sensitive to the distortion of the tetrahedral environment of the iron atoms. This sensitivity is extremely strong in a two-orbital (d_xz, d_yz) model due to the formation of a flat band around the Fermi level. Inclusion of the d_xy orbital destroys the flat band while keeping a considerable angle dependence in the band structure.