Structural parameters, electronic band structure, optical spectra, and thermoelectric properties of trigonal Ba₃B(Nb, Ta)₂O₉(B═Sr, Mg, Ca, Hg, Zn, Fe, Ni, Mn, Co, and Ca) compound materials are investigated. The computations are performed using density-functional calculations within the generalized gradient approximation. The calculated a and c parameters agree with those of the experiment to within 2%. The Ba₃B(Nb, Ta)₂O₉(B=Sr,Mg,Ca, Hg, Zn, Fe, Ni, Mn, Co, and Ca) materials are found to be semiconductors with a band-gap energy varying from 0.82 to 3.17 eV. A metallic character is observed in Ba₃B(Nb, Ta)₂O₉(B═Ni, Mn, and Co) compounds indicating the presence of conductivity features. A small carrier effective mass indicates the increase of the electron mobility leading to a high n-type conductivity. The p states dominate the lower valence band region. The optical spectra show an anisotropic character between x and z directions. The excitonic effects tend to increase the strength of the oscillator at M₀ and M points. The effect is reduced when increasing the photon energy, indicating that the Ba₃BB₂'O₉ compound can be used for devices such as Bragg's reflectors, and optical and optoelectronic devices. The calculations were performed using the BoltzTrap code, which depends on the semi-classical Boltzmann transport equation. The Seebeck coefficient, electrical conductivity, thermal conductivity, power factor, and the figure of merit for Ba₃(Fe, Sr, Hg, Zn)B′₂O₉ are calculated. At higher temperatures, the mobility increases by reducing the electrical conductivity. Ba₃(Fe, Sr, Hg, Zn) B₂' O₉ shows a considerable thermoelectric performance accompanied by a sign point figure of merit larger than many full perovskites reported till date.

中文翻译：

---

用于 Ba 基复杂钙钛矿化合物的光电子学候选材料的可能热电材料

_{三角Ba 3} B(Nb, Ta) ₂ O ₉ (B=Sr, Mg, Ca, Hg, Zn, Fe, Ni, Mn, Co, Ca)的结构参数、电子能带结构、光谱和热电性质研究了复合材料。使用广义梯度近似内的密度泛函计算来执行计算。计算出的 a 和 c 参数与实验的一致在 2% 以内。Ba ₃ B(Nb, Ta) ₂ O ₉ (B=Sr,Mg,Ca, Hg, Zn, Fe, Ni, Mn, Co, and Ca) 材料被发现是带隙能量从0.82 至 3.17 eV。在 Ba ₃ B(Nb, Ta) ₂ O _{9中观察到金属特征}(B=Ni、Mn 和 Co) 化合物表明存在导电特征。小的载流子有效质量表明电子迁移率的增加导致高的n型电导率。p态支配低价带区域。光谱显示x和z方向之间的各向异性特征。激子效应倾向于增加振荡器在M ₀和M点的强度。当增加光子能量时该效应减弱，表明 Ba ₃ BB ₂ 'O ₉该化合物可用于布拉格反射镜等器件，以及光学和光电器件。使用依赖于半经典玻尔兹曼输运方程的 BoltzTrap 代码进行计算。_{计算了 Ba 3} (Fe, Sr, Hg, Zn)B' ₂ O ₉的塞贝克系数、电导率、热导率、功率因数和品质因数。在较高温度下，迁移率通过降低电导率而增加。Ba ₃ (Fe, Sr, Hg, Zn) B ₂ ' O ₉显示出相当大的热电性能，并伴随着比迄今为止报道的许多全钙钛矿更大的符号点品质因数。