Abstract PdAs2 monolayer, a new pentagonal two-dimensional (2D) material, greatly attracts widely research interest due to its extremely high carrier mobility with a direct band gap. We have systematically studied the electronic structure, elastic, optical and thermal transport properties of monolayer PdAs2 from first-principles calculations. Our electronic structure calculations show that the monolayer PdAs2 is a semiconductor with a direct band gap of 0.78 eV. Tensile strain has a good regulating effect on the band gap, which can be adjusted from 0.01 eV to 0.84 eV. The calculated elastic constants of monolayer PdAs2 confirm that the PdAs2 monolayer is mechanically stable. The calculated optical properties reveal that the energy range of the absorption spectrum is 1 eV–15 eV. The absorption range of PdAs2 monolayer is mainly visible and ultraviolet light. Under the tensile strain, the absorption spectrum shows obvious redshift. With the increase of strain, the reflectivity and refractivity increase. The calculated thermal conductivity of the monolayer PdAs2 at 300 K is 1.04 W/(mK), which is lower than that of known pentagonal monolayer. In addition, the effects of phonon free path, group velocity and phonon scattering rate on lattice thermal conductivity are analyzed.

中文翻译：

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五-PdAs2 单层的电子、弹性、光学和热传输特性：第一性原理研究

摘要 PdAs2 单层是一种新型的五边形二维 (2D) 材料，由于其极高的载流子迁移率和直接带隙，引起了广泛的研究兴趣。我们从第一性原理计算系统地研究了单层 PdAs2 的电子结构、弹性、光学和热传输特性。我们的电子结构计算表明，单层 PdAs2 是一种直接带隙为 0.78 eV 的半导体。拉伸应变对带隙有很好的调节作用，可在0.01 eV到0.84 eV范围内调节。单层 PdAs2 的计算弹性常数证实了 PdAs2 单层是机械稳定的。计算出的光学性质表明吸收光谱的能量范围为 1 eV-15 eV。PdAs2 单层的吸收范围主要是可见光和紫外光。在拉伸应变下，吸收光谱显示出明显的红移。随着应变的增加，反射率和折射率增加。单层 PdAs2 在 300 K 下的计算热导率为 1.04 W/(mK)，低于已知的五边形单层的热导率。此外，分析了声子自由程、群速度和声子散射率对晶格热导率的影响。