Magnetic excitations in a three-orbital model for the strongly spin-orbit coupled iridates: Effect of mixing between the J=1/2 and 3/2 sectors

TL;DR

This paper presents a three-orbital model for iridates that accurately describes magnetic excitations and electronic structure, highlighting the mixing of J=1/2 and 3/2 sectors and matching RIXS experimental data.

Contribution

It introduces a unified three-orbital model that captures magnetic excitations and electronic structure, including sector mixing, in layered iridates.

Findings

Spin wave dispersions match RIXS data.

Strong AF zone boundary dispersion observed.

Evidence of J=1/2 and 3/2 sector mixing.

Abstract

A three-orbital-model approach for studying spin wave excitations in the strongly spin-orbit coupled layered perovskite iridates is presented which provides a unified description of magnetic excitations as well as the electronic band structure. The calculated spin wave dispersions with realistic three-band parameters are in excellent agreement with the RIXS data for iridates, including the strong AF zone boundary dispersion in the single-layer compound $\rm Sr_2 Ir O_4$ and the large anisotropy gap in the bilayer compound $\rm Sr_3 Ir_2 O_7$. The RIXS spin wave data is shown to provide evidence of mixing between the J=1/2 and 3/2 sectors in both compounds.