In recent years, there has been a fervent search for room-temperature superconductivity within the binary hydrides. However, as the number of untested compounds dwindled, it became natural to begin searching within the ternary hydrides. This led to the controversial discovery of room-temperature superconductivity at only 1 GPa in nitrogen-doped lutetium hydride [Dasenbrock-Gammon et al., Nature (London) 615, 244 (2023)] and consequently provided much impetus for the synthesis of nitrogen-based ternary hydrides. Here, we report the synthesis of stable trigonal ${\mathrm{LuH}}_3$ by hydrogenating pure lutetium which was subsequently pressurized to $\sim 2$ GPa in a dilute-${\mathrm{N}}_2$/He-rich pressure medium. Raman spectroscopy and x-ray diffraction were used to characterize the structures throughout. After depressurizing, energy-dispersive and wavelength-dispersive x-ray spectroscopies characterized the final compound. Though our compound under pressure exhibits similar structural behavior to the Dasenbrock-Gammon et al. sample, we do not observe any nitrogen within the structure of the recovered sample at ambient pressure. We observe two cubic structures under pressure that simultaneously explain the x-ray diffraction and Raman spectra observed: The first corresponds well to $Fm\overline{3}m {\mathrm{LuH}}_{2+x}$, while the latter is an $Ia\overline{3}$-type structure.

中文翻译：

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压力诱导形成由三角 LuH3 衍生的立方镥氢化物

近年来，人们热衷于寻找二元氢化物的室温超导性。然而，随着未经测试的化合物数量的减少，开始在三元氢化物中进行搜索变得很自然。这导致了氮掺杂氢化镥中仅 1 GPa 的室温超导性的有争议的发现 [Dasenbrock-Gammon等人，2017]。, Nature (London) 615 , 244 (2023)]，从而为氮基三元氢化物的合成提供了很大的动力。在这里，我们报告了稳定三角晶系的合成${\mathrm{卢赫}}_3$通过氢化纯镥，随后将其加压至$～2$ GPa 在稀-${\mathrm{氮}}_2$/富He压力介质。拉曼光谱和 X 射线衍射用于表征整个结构。减压后，能量色散和波长色散 X 射线光谱表征了最终化合物。尽管我们的化合物在压力下表现出与 Dasenbrock-Gammon等人相似的结构行为。样品，我们在环境压力下回收样品的结构中没有观察到任何氮。我们在压力下观察到两个立方结构，这同时解释了观察到的 X 射线衍射和拉曼光谱：第一个很好地对应于$F米\stackrel{￣}{3}米 {\mathrm{卢赫}}_{2+X}$，而后者是一个$我A\stackrel{￣}{3}$型结构。