First Principles Calculations of Fe on GaAs (100)

TL;DR

This study uses first principles calculations to analyze the electronic and magnetic properties of Fe layers on GaAs (100), revealing how Fe thickness influences magnetic moments, segregation behavior, and structural distortions.

Contribution

It provides detailed first-principles insights into Fe/GaAs (100) interfaces, including magnetic, segregation, and structural characteristics, which were not previously comprehensively modeled.

Findings

Fe magnetic moment depends on Fe-As distance

As segregates to the top of Fe film

Fe 3d-holes increase with Fe thickness

Abstract

We have calculated from first principles the electronic structure of 0.5 monolayer upto 5 monolayer thick Fe layers on top of a GaAs (100) surface. We find the Fe magnetic moment to be determined by the Fe-As distance. As segregates to the top of the Fe film, whereas Ga most likely is found within the Fe film. Moreover, we find an asymmetric in-plane contraction of our unit-cell along with an expansion perpendicular to the surface. We predict the number of Fe 3d-holes to increase with increasing Fe thickness on $p$-doped GaAs.