Abstract The mechanical, thermal and optical properties of newly predicted tetragonal NaGaS2 are reported by first-principle DFT calculations. In order to prove the reliability of the calculation method, we also calculated these properties of AgGaS2. The obtained values of AgGaS2 are in good accord with the existing experimental and theoretical data. The analysis of the elastic constants and modulus, anisotropy factors and the linear compressibilities indicates NaGaS2 crystal, having the stable mechanical structure, are the anisotropic material, and its ability to resist the compression is stronger than the shape change. The calculation of thermal property reflects a fact that NaGaS2 is a dynamically stable material, which is more suitable to be used as thermal insulating materials. Furthermore, the study on electronic structures and optical property shows that NaGaS2 is a wide band gap semiconductor material, and it is a promising candidate for optoelectronic materials in the ultraviolet energy region.

中文翻译：

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新预测的四方 NaGaS2 的机械、热和光学特性的理论研究

摘要 通过第一性原理 DFT 计算报告了新预测的四方 NaGaS2 的机械、热和光学性质。为了证明计算方法的可靠性，我们还计算了AgGaS2的这些性质。得到的 AgGaS2 值与现有的实验和理论数据吻合良好。弹性常数和模量、各向异性因子和线性压缩率的分析表明，NaGaS2晶体具有稳定的机械结构，是各向异性材料，其抗压缩能力强于形状变化。热性能的计算反映了NaGaS2是一种动态稳定的材料，更适合作为绝热材料使用。此外，