Covalency-driven collapse of strong spin-orbit coupling in face-sharing iridium octahedra

Mai Ye, Heung Sik Kim, Jae Wook Kim, Choong Jae Won, Kristjan Haule, David Vanderbilt, Sang Wook Cheong, G. Blumberg

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

We report ab initio density functional theory calculation and Raman scattering results to explore the electronic structure of Ba5CuIr3O12 single crystals. This insulating iridate, consisting of face-sharing IrO6 octahedra forming quasi-one-dimensional chains, cannot be described by the local jeff=1/2 moment picture commonly adopted for discussing the electronic and magnetic properties of iridate compounds with IrO6 octahedra. The shorter Ir-Ir distance in the face-sharing geometry, compared to corner- or edge-sharing structures, leads to strong covalency between neighboring Ir. Then, this strong covalency results in the formation of molecular orbitals (MOs) at each Ir trimer as the low-energy electronic degree of freedom. The theoretically predicted three-peak structure in the joint density of states, a distinct indication of deviation from the jeff=1/2 picture, is verified by observing the three-peak structure in the electronic excitation spectrum by Raman scattering.

Original languageEnglish (US)
Article number201105
JournalPhysical Review B
Volume98
Issue number20
DOIs
StatePublished - Nov 9 2018

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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