Effect of isoelectronic doping on honeycomb lattice iridate A_2IrO_3

S. Manni; Sungkyun Choi; I. I. Mazin; R. Coldea; Michaela Altmeyer; Harald O. Jeschke; Roser Valenti; P. Gegenwart

doi:10.1103/PhysRevB.89.245113

paper

Effect of isoelectronic doping on honeycomb lattice iridate A_2IrO_3

arXiv:1312.0815 · doi:10.1103/PhysRevB.89.245113

Abstract

We have investigated experimentally and theoretically the series (Na $_{1 - x}$ Li $_{x}$ ) $_{2}$ IrO $_{3}$ . Contrary to what has been believed so far, only for $x \leq 0.25$ the system forms uniform solid solutions. For larger Li content, as evidenced by powder X-ray diffraction, scanning electron microscopy and density functional theory calculations, the system shows a miscibility gap and a phase separation into an ordered Na $_{3}$ LiIr $_{2}$ O $_{6}$ phase with alternating Na $_{3}$ and LiIr $_{2}$ O $_{6}$ planes, and a Li-rich phase close to pure Li $_{2}$ IrO $_{3}$ . For $x \leq 0.25$ we observe (1) an increase of $c / a$ with Li doping up to $x = 0.25$ , despite the fact that $c / a$ in pure Li $_{2}$ IrO $_{3}$ is smaller than in Na $_{2}$ IrO $_{3}$ , and (2) a gradual reduction of the antiferromagnetic ordering temperature $T_{N}$ and ordered moment. The previously proposed magnetic quantum phase transition at $x \approx 0.7$ may occur in a multiphase region and its nature needs to be re-evaluated.

8 pages, 9 figures including supplemental information

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Quantum spin Hall effect in a transition metal oxide Na2IrO3

Effect of isoelectronic doping on honeycomb lattice iridate A_2IrO_3

Abstract

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