Abstract The discovery of two-dimensional (2D) Ga2O3 has provided an efficient way to design high performance Ga2O3 devices. Here, mechanical and thermodynamic properties of 2D Ga2O3 are important parameters in device design but very few studies are investigated by density functional theory. Results show that 2D Ga2O3 retains the monoclinic character with thirteen independent elastic constants which meet with the mechanical stability criteria, and irrespective of its thickness. Interestingly, although the elastic constant C11 is lower than C22 and C33, 2D Ga2O3 may be harder to be compressed along the a direction. Meanwhile, the elastic constant C44 is larger than C55 and C66, in contrast to that of bulk β-Ga2O3. Upon decreasing the thickness of 2D Ga2O3, the elastic properties continue reduce and lower than those of 2D layered materials, but their compressive anisotropic properties are enhanced and larger than those of bulk β-Ga2O3. The thermal conductivity and capacity of monolayer Ga2O3 are enhanced to 0.49 W∙cm−1∙K−1, and 27.58 J∙mol−1∙K−1, respectively. Such variations of bulk-transition-2D Ga2O3 are opposite to those of bulk-transition-2D GaN due to the recombined orbitals of GaN. These results are crucial to the device design based on 2D Ga2O3.

中文翻译：

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二维单斜晶系 Ga2O3 的力学和热力学性质

摘要 二维 (2D) Ga2O3 的发现为设计高性能 Ga2O3 器件提供了一种有效的方法。在这里，二维 Ga2O3 的机械和热力学性质是器件设计中的重要参数，但很少有研究通过密度泛函理论进行研究。结果表明，二维 Ga2O3 保留了单斜晶特性，具有 13 个独立的弹性常数，符合机械稳定性标准，且与其厚度无关。有趣的是，虽然弹性常数 C11 低于 C22 和 C33，但二维 Ga2O3 可能更难沿 a 方向压缩。同时，与块体 β-Ga2O3 相比，弹性常数 C44 大于 C55 和 C66。随着二维 Ga2O3 厚度的减小，其弹性性能继续降低并低于二维层状材料，但它们的压缩各向异性特性比块状 β-Ga2O3 增强且更大。单层 Ga2O3 的热导率和容量分别提高到 0.49 W∙cm−1∙K−1 和 27.58 J∙mol−1∙K−1。由于 GaN 的重新组合轨道，体转变 2D Ga2O3 的这种变化与体转变 2D GaN 的变化相反。这些结果对于基于 2D Ga2O3 的器件设计至关重要。