Reexamination of the charge-ordered dimer pattern in the spinel compound CuIr2S4 using single-crystal synchrotron x-ray diffraction

TL;DR

This study reexamines the low-temperature crystal structure of CuIr2S4 using single-crystal synchrotron x-ray diffraction, revealing differences in charge ordering and dimer arrangements compared to previous powder-based analyses.

Contribution

It provides a revised structural model of CuIr2S4's low-temperature phase with detailed parameters, enhancing understanding of its charge ordering and dimerization patterns.

Findings

Confirmed Ir dimer formation with charge ordering

Identified different charge pattern and dimer arrangement from previous studies

Provided detailed structural parameters for future physical property investigations

Abstract

We have re-investigated the crystal structure of a spinel type CuIr2S4 at low temperatures using a single-crystal in a synchrotron radiation x-ray diffraction experiment. The crystal structure of the low-temperature phase of CuIr2S4 has been already studied by diffraction experiments using a powder sample, and it has been reported that the formation of dimer molecules accompanied by charge ordering of Ir has been achieved. The crystal structure of the low-temperature phase obtained in our reanalysis was the same as the previously reported structure in that it showed the formation of Ir dimers accompanied by charge ordering, but the charge ordering pattern and arrangement of the dimers in the unit cell were different. We will discuss the validity of the structure obtained in this study and provide the structural parameters revealed in the reanalysis. The results of this study should provide a basis for further studies of the physical properties of CuIr2S4, which are still being actively investigated.