In this study, we carried out ab-initio calculations of structural, electronic, optical and thermo-electric properties of CaTaO2N compound in Pnma orthorhombic structure, using the full-potential linearized augmented plane wave method (FP-LAPW), within the framework of density functional theory (DFT). The calculated structural parameters are found to be in good agreement with the experimental results. Moreover, we have studied the electronic band structure, total and partial density of states in order to explain the origin of band gaps and the nitrogen anion contribution in the valence and the conduction bands. The CaTaO2N band structure has shown a direct band gap in the direction [Formula: see text] (with the value 2.32[Formula: see text]eV). The optical properties represented by the dielectric functions for CaTaO2N compound have revealed that the Pnma structure absorbs the light at a large window in the edge UV-Vis regions. In order to explain the thermo-electric properties, we have calculated Seebeck coefficient, electrical conductivity, thermal conductivity and the factor figure of merit in this temperature range 100–1000 K. The factor figure of mérit (ZT) of CaTaO2N takes a maximum value of 0.775 at [Formula: see text][Formula: see text]K.

中文翻译：

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氧氮化钙钛矿CaTaO2N的结构、电子、光学和热电性能

在这项研究中，我们对 CaTaO 的结构、电子、光学和热电特性进行了从头算计算。2在密度泛函理论 (DFT) 的框架内，采用全势线性化增强平面波法 (FP-LAPW)，采用 Pnma 正交结构中的 N 化合物。计算得到的结构参数与实验结果吻合较好。此外，我们研究了电子能带结构、总态密度和部分态密度，以解释带隙的起源以及价带和导带中氮阴离子的贡献。氧化钙2N能带结构在方向[公式：见正文]（值为2.32[公式：见正文]eV）上显示出直接带隙。由 CaTaO 的介电函数表示的光学性质2N 化合物揭示了 Pnma 结构在边缘 UV-Vis 区域的大窗口处吸收光。为了解释热电特性，我们计算了100-1000 K温度范围内的塞贝克系数、电导率、热导率和品质因数。CaTaO的品质因数（ZT）2N 在 [公式：见文本][公式：见文本]K 处取最大值 0.775。