Electronic correlations in short period (CrAs)$_n$/(GaAs)$_n$ ferromagnetic heterostructures

TL;DR

This study examines how electronic correlations affect half-metallicity in CrAs/GaAs heterostructures with small periods, revealing temperature-dependent suppression of the half-metallic gap and layer-specific localization of electronic states.

Contribution

It provides a combined many-body and electronic structure analysis of correlation effects in short-period heterostructures, highlighting temperature impacts on half-metallicity and state localization.

Findings

Minority spin gap shrinks with increasing heterostructure period.

Finite temperature reduces spin polarization at the Fermi level by at least 25%.

Electrons and holes tend to localize in different layers, maintaining layer separation.

Abstract

We investigate half-metallicity in [001] stacked (CrAs)$_n$/(GaAs)$_n$ heterostructures with $n \leq 3$ by means of a combined many-body and electronic structure calculation. Interface states in the presence of strong electronic correlations are discussed for the case $n=1$. For $n=2,3$ our results indicate that the minority spin half-metallic gap is suppressed by local correlations at finite temperatures, and continuously shrinks upon increasing the heterostructure period. Although around room temperature the magnetization of the heterostructure deviates by only $2%$ from the ideal integer value, finite temperature polarization at $E_F$ is reduced by at least $25%$. Below the Fermi level the minority spin highest valence states are found to localize more on the GaAs layers while lowest conduction states have a many-body origin. Our results, therefore, suggest that in these heterostructures holes and electrons remain separated among different layers.