Ab initio investigation of FeAs/GaAs heterostructures for potential spintronic and superconducting applications

TL;DR

This study uses first-principles calculations to analyze FeAs/GaAs heterostructures, revealing their magnetic properties and implications for spintronic and superconducting applications.

Contribution

It provides the first detailed ab initio investigation of FeAs/GaAs heterostructures, highlighting their magnetic ordering and electronic structure.

Findings

Fermi surface is altered by interactions with GaAs layers.

Lowest energy magnetic state is always antiferromagnetic.

Heterostructures are unlikely to be effective for spintronics.

Abstract

Ultra-thin FeAs is of interest both as the active component in the newly identified pnictide superconductors, and in spintronic applications at the interface between ferromagnetic Fe and semiconducting GaAs. Here we use first-principles density functional theory to investigate the properties of FeAs/GaAs heterostructures. We find that the Fermi surface is modified from that characteristic of the pnictide superconductors by interactions between the FeAs layer and the As atoms in the GaAs layers. Regardless of the number of FeAs layers, the Fe to As ratio, or the strain state, the lowest energy magnetic ordering is always antiferromagnetic, suggesting that such heterostructures are not promising spintronic systems, and offering an explanation for the failure of spin injection across Fe/GaAs interfaces.