研究目的
To report the previously unreported oxygen excess hexagonal antimony tungsten bronze, h-SbxWO3 + 2x with x = 0.167, and characterize its structure, properties, and analogy to classical tungsten bronzes.
研究成果
The discovery of h-SbxWO3 + 2x bridges a gap in antimony tungsten bronze chemistry, confirming it as the first with antimony in SbV oxidation state. It exhibits metallic behavior with low density of states at the Fermi level but no superconductivity, contrasting with alkali tungsten bronzes. Future work could explore electron doping or phonon softening to induce superconductivity.
研究不足
The synthesis is sensitive to temperature and oxygen content, with a narrow formation range (580-620°C). The compound may contain impurities if stoichiometry is not precise. DFT calculations used a simplified model that does not fully account for structural disorder, potentially limiting accuracy. No superconductivity was observed, which may be due to disruptions from antimony or oxygen in the channels.
1：Experimental Design and Method Selection:
The study involved synthesis of polycrystalline and single-crystal samples, structural characterization using X-ray diffraction (single-crystal and powder), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), physical property measurements (resistivity and magnetization), and electronic structure calculations using density functional theory (DFT).
2：Sample Selection and Data Sources:
Samples were synthesized from precursors including WO3 (
3：998%), Sb2O5 (998%), and WO2, with precise stoichiometry for h-SbxWO3 + 2x. Single crystals were grown using LiCl flux. List of Experimental Equipment and Materials:
Equipment includes Bruker D8 VENTURE diffractometer for single-crystal XRD, Bruker D8 Advance Eco for PXRD, JEOL 3000F microscope for TEM, ThermoFisher Ka XPS spectrometer, Quantum Design PPMS for resistivity and magnetization measurements, and WIEN2K code for DFT calculations. Materials include WO3, Sb2O5, WO2, LiCl, corundum crucibles, quartz glass tubes, silver paint, and platinum wire.
4：Experimental Procedures and Operational Workflow:
Synthesis involved heating mixtures in evacuated quartz tubes at 600°C for 12 hours for polycrystalline samples, and using LiCl flux at 600°C for 10 days for single crystals. Structural characterization involved data collection and refinement using specified software. Physical measurements were conducted over temperature ranges from 140 mK to 300 K.
5：Data Analysis Methods:
Structural data were refined using SHELXL-2013. XPS data were deconvoluted to identify oxidation states. Resistivity data were analyzed using standard 4-probe techniques. DFT calculations used the Perdew-Burke-Ernzerhof parametrization.
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