Antiferromagnetic superexchange interactions in LaOFeAs

TL;DR

This study uses first-principles calculations to analyze the magnetic interactions in LaOFeAs, revealing collinear antiferromagnetic order driven by superexchange interactions, which may influence superconductivity mechanisms.

Contribution

It provides a detailed first-principles analysis of magnetic interactions and their role in structural transitions and superconductivity in LaOFeAs.

Findings

Fe spins are collinear antiferromagnetically ordered

Magnetic interactions drive the structural transition

Antiferromagnetic fluctuations are important for superconductivity

Abstract

From first-principles calculations, we have studied the electronic and magnetic structures of the ground state of LaOFeAs. The Fe spins are found to be collinear antiferromagnetic ordered, resulting from the interplay between the strong nearest and next-nearest neighbor superexchange antiferromagnetic interactions. The structure transition observed by neutron scattering is shown to be magnetically driven. Our study suggests that the antiferromagnetic fluctuation plays an important role in the Fe-based superconductors. This sheds light on the understanding of the pairing mechanism in these materials.