Robustness of basal-plane antiferromagnetic order and the $J_{eff}=1/2$ state in single-layer iridate spin-orbit Mott insulators

TL;DR

This study investigates the magnetic structure and electronic ground state of Ba2IrO4, revealing a robust antiferromagnetic order and a $J_{eff}=1/2$ state similar to Sr2IrO4, despite structural differences, emphasizing the role of spin-orbit coupling.

Contribution

It provides new experimental evidence that the $J_{eff}=1/2$ state and antiferromagnetic order are robust in Ba2IrO4, highlighting the influence of spin-orbit interaction in 5d oxides.

Findings

Ba2IrO4 exhibits a similar antiferromagnetic order to Sr2IrO4.

The electronic ground state in Ba2IrO4 is consistent with a $J_{eff}=1/2$ model.

The key electronic properties are robust against structural differences.

Abstract

The magnetic structure and electronic groundstate of the layered perovskite Ba2IrO4 have been investigated using x-ray resonant magnetic scattering (XRMS). Our results are compared with those for Sr2IrO4, for which we provide supplementary data on its magnetic structure. We find that the dominant, long-range antiferromagnetic order is remarkably similar in the two compounds, and that the electronic groundstate in Ba2IrO4, deduced from an investigation of the XRMS $L_3/L_2$ intensity ratio, is consistent with a $J_{eff}=1/2$ description. The robustness of these two key electronic properties to the considerable structural differences between the Ba and Sr analogues is discussed in terms of the enhanced role of the spin-orbit interaction in 5d transition metal oxides.