Strain and correlation induced half-metallic ferromagnetism in orthorhombic BaFeO$_{3}$

TL;DR

This study uses first-principles calculations to explore how strain and electron correlation effects induce half-metallic ferromagnetism in orthorhombic BaFeO₃, revealing tunable electronic and magnetic properties.

Contribution

It demonstrates that strain and Hubbard U can induce and control half-metallicity in BaFeO₃, providing insights into its electronic and magnetic tunability.

Findings

Large tensile strain induces half-metallicity in BaFeO₃.

Including Hubbard U induces half-metallicity without strain.

Magnetic moments are robust against ~10% strain.

Abstract

Using first-principles calculations, the electronic and magnetic properties of orthorhombic BaFeO$_{3}$ (BFO) are investigated with local spin density approximation (LSDA). The calculations reveal that at the optimized lattice volume BFO has a lower energy in ferromagnetic state as compared with antiferromagnetic state. At the equilibrium volume, BFO shows metallic behavior, however, under a large tensile strain ($\sim25\%$), BFO shows half-metallic behavior consistent with the integer magnetic moment of $4.0\mu_{\rm{B}}$/fu mainly caused by the $t_{2g}$ and $e_{g}$ electrons of Fe. Including a Hubbard-like contribution $U$ (LSDA$+U$) on Fe $d$ states induced half-metallic bahvior without external strain, which indicates that $U$ can be used to tune the electronic structure of BFO. The magnetic moments remained robust against $\sim 10\%$ compressive and tensile strain. At large compressive (tensile) strain, the half-metallicity of BFO is mainly destroyed by the Fe-$d$ (O-$p$) electrons in agreement with the non-integer value of the magnetic moments of BFO.