Optical spectroscopic investigation on the temperature-dependent electronic structure evolution of the Jeff,1/2 Mott insulator Sr2IrO4

TL;DR

This study uses optical spectroscopy to explore how the electronic structure of Sr2IrO4 changes with temperature, revealing a decreasing Mott gap and providing insights into underlying physical mechanisms.

Contribution

It presents the first detailed temperature-dependent optical spectroscopy analysis of Sr2IrO4, linking experimental results with first-principles calculations to understand electronic structure evolution.

Findings

Decrease in Mott gap with increasing temperature

Significant changes in optical conductivity peaks

Correlation with lattice distortion and magnetic ordering

Abstract

We investigated the temperature-dependent evolution of the electronic structure of the Jeff,1/2 Mott insulator Sr2IrO4 using optical spectroscopy. The optical conductivity spectra $\sigma(\omega)$ of this compound has recently been found to exhibit two d-d transitions associated with the transition between the Jeff,1/2 and Jeff,3/2 bands due to the cooperation of the electron correlation and spin-orbit coupling. As the temperature increases, the two peaks show significant changes resulting in a decrease in the Mott gap. The experimental observations are compared with the results of first-principles calculation in consideration of increasing bandwidth. We discuss the effect of the temperature change on the electronic structure of Sr2IrO4 in terms of local lattice distortion, excitonic effect, electron-phonon coupling, and magnetic ordering.