Two-dimensional (2D) materials, with their structural uniqueness, exceptional properties, and wide-ranging applications, show unprecedented prospects in fundamental physics research and industrial applications. 2D \b{eta}-phase cuprous iodide (\b{eta}-CuI) is a promising candidate for overcoming the challenges of insufficient P-type transparent conductive materials, with multiple predicted unique properties. Previous experimental results show that \b{eta}-CuI only occurs at elevated temperatures between 645 and 675 K. Many efforts are made to stabilize \b{eta}-CuI at room temperature through surface/interface engineering. However, the resulting composites limit the performance and application of pure 2D \b{eta}-CuI. Here, we demonstrate experimentally that isolated 2D \b{eta}-CuI single crystals can exist stably under ambient conditions, a high-temperature phase CuI found at room temperature. We validate the simultaneous existence of {\gamma}-CuI and \b{eta}-CuI in the synthesized CuI. The previous neglect of \b{eta}-CuI crystals can be ascribed to factors including their low content, small dimensions, and lack of ingenious experimental characterization. Moreover, the theoretical calculation further confirms dynamically and thermally stable of the monolayer \b{eta}-CuI, which has an ultra-wide direct band-gap (3.66 eV). Our findings challenge the traditional understanding of \b{eta}-CuI as a high-temperature phase of CuI, instead providing a new definition that 2D \b{eta}-CuI exhibits remarkable stability under ambient conditions.

中文翻译：

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常温条件下高温相碘化亚铜二维单晶

二维（2D）材料以其独特的结构、优异的性能和广泛的应用，在基础物理研究和工业应用中展现出前所未有的前景。二维\b{eta}相碘化亚铜（\b{eta}-CuI）是克服P型透明导电材料不足挑战的有前途的候选材料，具有多种预测的独特性能。先前的实验结果表明，β-CuI仅在645至675 K之间的高温下出现。通过表面/界面工程，人们做出了许多努力以在室温下稳定β-CuI。然而，所得复合材料限制了纯二维\b{eta}-CuI的性能和应用。在这里，我们通过实验证明了孤立的二维\b{eta}-CuI单晶可以在环境条件下稳定存在，室温下发现的高温相 CuI。我们验证了合成的 CuI 中同时存在 {\gamma}-CuI 和 \b{eta}-CuI。先前对 β-CuI 晶体的忽视可归因于其含量低、尺寸小以及缺乏巧妙的实验表征等因素。此外，理论计算进一步证实了单层b{eta}-CuI具有超宽直接带隙（3.66 eV）的动态和热稳定性。我们的研究结果挑战了将\b{eta}-CuI作为CuI的高温相的传统理解，而是提供了一个新的定义，即二维\b{eta}-CuI在环境条件下表现出显着的稳定性。先前对 β-CuI 晶体的忽视可归因于其含量低、尺寸小以及缺乏巧妙的实验表征等因素。此外，理论计算进一步证实了单层b{eta}-CuI具有超宽直接带隙（3.66 eV）的动态和热稳定性。我们的研究结果挑战了将\b{eta}-CuI作为CuI的高温相的传统理解，而是提供了一个新的定义，即二维\b{eta}-CuI在环境条件下表现出显着的稳定性。先前对 β-CuI 晶体的忽视可归因于其含量低、尺寸小以及缺乏巧妙的实验表征等因素。此外，理论计算进一步证实了单层b{eta}-CuI具有超宽直接带隙（3.66 eV）的动态和热稳定性。我们的研究结果挑战了将\b{eta}-CuI作为CuI的高温相的传统理解，而是提供了一个新的定义，即二维\b{eta}-CuI在环境条件下表现出显着的稳定性。它具有超宽的直接带隙（3.66 eV）。我们的研究结果挑战了将\b{eta}-CuI作为CuI的高温相的传统理解，而是提供了一个新的定义，即二维\b{eta}-CuI在环境条件下表现出显着的稳定性。它具有超宽的直接带隙（3.66 eV）。我们的研究结果挑战了将\b{eta}-CuI作为CuI的高温相的传统理解，而是提供了一个新的定义，即二维\b{eta}-CuI在环境条件下表现出显着的稳定性。