Orbital ordering of Ir-t2g states in the double perovskite Sr2CeIrO6

Abstract

The electronic and magnetic properties of monoclinic double perovskite Sr${}_2$CeIrO${}_6$ were examined based on both experiments and first-principles density functional theory calculations. From the calculations we conclude that low-spin-state Ir${}^{4+}$ (5${\text{d}}^5$, S=$\frac{1}{2}$) shows t${}_{2g}$ band derived anti-ferro type orbital ordering implying alternating occupations of ${\text{d}}_{yz}$ and ${\text{d}}_{xz}$ orbitals at the two symmetrically independent Ir sites. The experimentally determined Jahn-Teller type distorted monoclinic structure is consistent with the proposed orbital ordering picture. Surprisingly, the Ir-5$\text{d}$ orbital magnetic moment was found to be $\approx$ 1.3 times larger than the spin magnetic moment. The experimentally observed AFM-insulating states are consistent with the calculations. Both electron-electron correlation and spin-orbit coupling (SOC) are required to drive the experimentally observed AFM-insulating ground state. This single active site double perovskite provides a rare platform with a prototype geometrically frustrated fcc lattice where among the different degrees of freedom (i.e spin, orbital, and lattice), spin-orbit interaction and Coulomb correlation energy scales compete and interact with each other.

5 pages, 3 figures

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Cited by in corpus (10)

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• Coulomb Correlations in 4d and 5d Oxides from First Principles - or How Spin-Orbit Materials choose their Effective Orbital Degeneracies
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• Coupling of lattice, spin and intra-configurational excitations of Eu3+ in Eu2ZnIrO6
• Structural and metal-insulator transitions in rhenium based double perovskites via orbital ordering
• Structural, electronic, and magnetic properties of nearly-ideal $J_{\mathrm{eff}}$ $=$ 1/2 iridium halides
• Low temperature ferromagnetism in perovskite SrIrO${}_3$ films
• Strain induced changes of electronic properties of B-site ordered double perovskite Sr${}_2$CoIrO${}_6$ thin films
• $J_{eff}$ states in a quasi one dimensional antiferromagnetic spin chain hexagonal Iridates Sr${}_3$MIrO${}_6$ (M=Mg, Zn, Cd): an $ab-initio$ comparative perspective
• Emergence of bond-dependent highly anisotropic magnetic interactions in Sr${}_4$RhO${}_6$: a theoretical study