1. Structural Diversity in Oxoiridates with 1D Ir n O 3( n +1) Chain Fragments and Flat Bands.
- Author
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Guo S, Mitchell Warden HE, and Cava RJ
- Abstract
A previously unreported series of hexagonal-perovskite-based Rb-oxoiridates, Rb
5 Ir2 O9 , Rb7 Ir3 O12 , and Rb12 Ir7 O24 , have been synthesized and structurally analyzed via N2 -protected single-crystal X-ray diffraction (SC-XRD). These materials exhibit different 1D Irn O3( n +1) chain fragments along their c axes. IrO6 octahedra and RbOx ( x = 6, 8, and 10) polyhedra are their basic building blocks. The IrO6 octahedra are linked via face-sharing, forming Ir2 O9 dimers, Ir3 O12 trimers, and Ir7 O24 heptamers. The nonmagnetic RbOx ( x = 6, 8, and 10) polyhedra serve as both bridging units and spacers. Temperature-dependent SC-XRD shows all three to display positive thermal expansion and rules out structural transitions from their triangular symmetries down to 100 K. Density functional theory results suggest semiconducting-like behavior for the title compounds. The flatness of the electronic bands and our structural analysis are of potential interest for understanding and designing 1D quantum materials.- Published
- 2022
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