Pseudo-half-metalicity in the double perovskite Sr$_2$CrReO$_6$ from density-functional calculations

TL;DR

This study uses density-functional calculations to analyze the electronic and magnetic properties of Sr$_2$CrReO$_6$, revealing a transition from half-metallicity to pseudo-half-metallicity due to spin-orbit coupling, and discussing implications for experimental observations.

Contribution

It provides a detailed theoretical analysis of the electronic structure of Sr$_2$CrReO$_6$, highlighting the effects of spin-orbit coupling and disorder on its magnetic properties.

Findings

Scalar relativistic calculations predict half-metallicity with 1 μ_B magnetic moment.

Including spin-orbit coupling closes the half-metallic gap, creating a pseudo-gap.

Calculated magnetic moment (1.28 μ_B) exceeds experimental value (0.9 μ_B).

Abstract

The electronic structure of the spintronic material Sr$_2$CrReO$_6$ is studied by means of full-potential linear muffin-tin orbital method. Scalar relativistic calculations predict Sr$_2$CrReO$_6$ to be half-metallic with a magnetic moment of 1 $\mu_B$. When spin-orbit coupling is included, the half-metallic gap closes into a pseudo-gap, and an unquenched rhenium orbital moment appears, resulting in a significant increase of the total magnetic moment to 1.28 $\mu_B$. This moment is significantly larger than the experimental moment of 0.9 $\mu_B$. A possible explanation of this discrepancy is that the anti-site disorder in Sr$_2$CrReO$_6$ is significantly larger than hitherto assumed.