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Nature of the Insulating Ground State of the 5d Postperovskite CaIrO3

TitleNature of the Insulating Ground State of the 5d Postperovskite CaIrO3
Publication TypeJournal Article
Year of Publication2015
AuthorsKim, SW, Liu, C, Kim, HJ, Lee, JH, Yao, YX, Ho, KM, Cho, JH
JournalPhysical Review Letters
Date Published08
Type of ArticleArticle
ISBN Number0031-9007
Accession NumberWOS:000360065900011
Keywordsphase, sr2iro4

The insulating ground state of the 5d transition metal oxide CaIrO3 has been classified as a Mott-type insulator. Based on a systematic density functional theory (DFT) study with local, semilocal, and hybrid exchange-correlation functionals, we reveal that the Ir t(2g) states exhibit large splittings and one-dimensional electronic states along the c axis due to a tetragonal crystal field. Our hybrid DFT calculation adequately describes the antiferromagnetic (AFM) order along the c direction via a superexchange interaction between Ir4+ spins. Furthermore, the spin-orbit coupling (SOC) hybridizes the t(2g) states to open an insulating gap. These results indicate that CaIrO3 can be represented as a spin-orbit Slater insulator, driven by the interplay between a long-range AFM order and the SOC. Such a Slater mechanism for the gap formation is also demonstrated by the DFT + dynamical mean field theory calculation, where the metal-insulator transition and the paramagnetic to AFM phase transition are concomitant with each other.

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Exploratory Theory