Implications of electron and hole doping on the magnetic properties of spin-orbit entangled Ca$_\text{4}$IrO$_\text{6}$ from DFT calculations

TL;DR

This study uses DFT calculations to explore how electron and hole doping affect the electronic and magnetic properties of Ca4IrO6, revealing persistent antiferromagnetism with complex spin arrangements despite doping-induced metallicity.

Contribution

It provides new insights into the effects of doping on the magnetic structure and spin-orbit interactions in Ca4IrO6, a $J_{eff}=1/2$ iridate, highlighting potential spintronic applications.

Findings

Doping turns the insulator into a conductor.

Antiferromagnetism persists after doping.

Strong spin-orbit coupling causes noncollinear spins.

Abstract

We investigate the electronic structure and magnetic properties of a $J_\text{eff} = 1/2$ iridate Ca$_4$IrO$_6$ and the implications of doping electrons and holes using ab initio density functional theory. Our calculations considering spin-orbit interaction reveal that although the Mott-insulating parent compound transforms into a conductor upon doping, antiferromagnetism sustains in the doped system, albeit with a grossly noncollinear arrangement of the spins. We find a strong spin-orbit interaction and magneto-crystalline anisotropy, causing frustration in the system, possibly leading to the highly noncollinear arrangement of spins upon non-magnetic doping. Our results may be important from the viewpoint of spintronics using iridates or other $5d$ materials.