A first principles study on FeAs single layers

TL;DR

This study uses first-principles calculations to analyze FeAs single layers, revealing significant differences from bulk materials and questioning their suitability as models for Fe-based superconductors.

Contribution

It demonstrates that FeAs single layers do not replicate bulk properties, highlighting the importance of interlayer interactions in Fe-based superconductors.

Findings

FeAs single layers have different geometric and electronic structures from bulk materials.

Bulk magnetic ground states are not reproduced in single layers.

Fe-As distance behavior upon doping differs from bulk materials.

Abstract

FeAs- single layer is tested as a simple model for LaFeAsO and BaFe2As2 based on first-principles calculations using generalized gradient approximation (GGA) and GGA+U. The calculated single- layer geometric and electronic structures are inconsistent with that of bulk materials. The bulk collinear antiferromagnetic ground state is failed to be obtained in the FeAs- single layer. The monotonous behavior of the Fe-As distance in z direction upon electron or hole doping is also in contrast with bulk materials. Our results indicate that, in LaFeAsO and BaFe2As2, interactions between FeAs layer and other layers beyond simple charge doping are important, and a single FeAs layer may not represent a good model for Fe based superconducting materials.