Related papers: The Chemical Instability of Na2IrO3 in Air
Extensive X-ray and neutron scattering experiments and additional transmission electron microscopy results reveal the partial decomposition of Nd2-xCexCuO4 (NCCO) in a low-oxygen-fugacity environment such as that typically realized during…
Li3Co2SbO6 is prepared by molten salt ion exchange and its structure refined by the Rietveld method confirming the honeycomb-type Co/Sb ordering of its Na precursor. Monoclinic rather than trigonal symmetry of Na3Co2SbO6 is directly…
A new-type structural transition has been found in Li2RuO3 with honeycomb lattice of edge-sharing RuO6-octahedra. With decreasing temperature T, the electrical resistivity exhibits an anomalous increase at T=Tc~540 K, suggesting the (metal…
We report results of our study of a newly synthesized honeycomb iridate NaxIrO3 (0.60 < x < 0.80). Single-crystal NaxIrO3 adopts a honeycomb lattice noticeably without distortions and stacking disorder inherently existent in its sister…
The synthesis of IrI$_3$ at high pressure in its layered honeycomb polymorph is reported. Its crystal structure is refined by single crystal X-ray diffraction. Faults in the honeycomb layer stacking are observed by single crystal…
The crystal structure of Na0.5CoO2, determined by powder neutron diffraction, is reported. The structure consists of layers of edge-shared CoO6 octahedra in a triangular lattice, with Na ions occupying ordered positions in the interleaving…
A systematic study of NaxCoO2 (x=0.50 - 0.90) and NaxCoO2 yH(D)2O (x=0.26 - 0.42, y=1.3) has been performed to determine phase stability and the effect of hydration on the structural and superconducting properties of this system. We show…
The honeycomb lattice material Li2RuO3 undergoes a dimerization of Ru4+ cations on cooling below 270C, where the magnetic susceptibility vanishes. We use density functional theory calculations to show that this reflects the formation of a…
$\mathrm{Cu_2IrO_3}$ is among the newest layered honeycomb iridates and a promising candidate to harbor a Kitaev quantum spin liquid state. Here, we investigate the pressure and temperature dependence of its structure through a combination…
We have carried out systematic temperature-dependent neutron diffraction measurements in conjunction with dielectric spectroscopy from 6 to 300 K for sodium niobate based compounds (1-x) NaNbO3 -xBaTiO3 (NNBTx). The dielectric constant is…
We report the observation of a stepwise "melting" of the low-temperature Na-vacancy order in the layered transition metal oxide Na0.7CoO2. High-resolution neutron powder diffraction indicates the existence of two first-order structural…
The complex structures and electronic properties of alkali metals and their alloys provide a natural laboratory for studying the interelectronic interactions of metals under compression. A recent theoretical study (J. Phys. Chem. Lett.…
We report neutron powder diffraction measurements on a series of NaxCoO2 samples with x near 0.75 which were prepared under different synthesis conditions. Two different crystal structures for the samples are observed at room temperature.…
Honeycomb Na$_2$IrO$_3$ is a prototype spin-orbit Mott insulator and Kitaev magnet. We report a combined structural and electrical resistivity study of Na$_2$IrO$_3$ single crystals. Laue back-scattering diffraction indicates twinning with…
Many layered materials can be cleaved down to individual atomic planes, similar to graphene, but only a small minority of them are stable under ambient conditions. The rest reacts and decomposes in air, which has severely hindered their…
The crystal structures of the NaxCoO2 phases based on three-layer NaCoO2, with x=0.32, x=0.51, x=0.60, x=0.75 and x=0.92, determined by powder neutron diffraction, are reported. The structures have triangular CoO2 layers interleaved by…
Through powder x-ray diffraction we have investigated the structural behavior of SmVO3, in which orbital and magnetic degrees of freedom are believed to be closely coupled to the crystal lattice. We have found, contrary to previous reports,…
A new layered iron-oxychalcogenide Na2Fe2OSe2 has been synthesized and structurally characterized by powder X-ray diffraction. The structure is formed by alternate stacking of the newly discovered [Fe2OSe2] blocks and double layers of Na.…
The Kitaev honeycomb model has been suggested as a useful starting point to describe the honeycomb iridates. However, the zigzag ordering seen in Na2IrO3 and the magnetic transition in Li2IrO3 have raised questions to their connection to…
We report the synthesis and characterisation of polycrystalline Na$_2$RuO$_3$, a layered material in which the Ru$^{4+}$ ($4d^4$ configuration) form a honeycomb lattice. The optimal synthesis condition was found to produce a nearly ordered…