Allan Lynet, Mulwa Winfred M, Mwabora Julius M, Musembi Robinson J, Mapasha R E
Department of Physics, Faculty of Science and Technology, University of Nairobi, P.O.Box 30197-00100, Nairobi, Kenya.
Department of Physics, Faculty of Science, Egerton University, P.O Box 536-20115, Egerton, Kenya.
Heliyon. 2023 Jul 26;9(8):e18531. doi: 10.1016/j.heliyon.2023.e18531. eCollection 2023 Aug.
In this study, the structural, electronic, mechanical, optical, and thermoelectric properties of the cubic half-Heusler compound ZrCoY(Y[bond, double bond]Sb and Bi) obtained using first-principles calculations are presented. The following exchange-correlation functionals have been employed: Generalized Gradient Approximation with Perdew-Burke-Ernzerhoff (GGA-PBE), Generalized Gradient Approximation with Perdew-Burke-Enzerhoff for solids (GGA-PBESol) and Local Density Approximation (LDA). Both ZrCoSb and ZrCoBi compounds are mechanically and dynamically stable, based on the elastic and phonon properties analysis. The calculated electronic band gaps for both compounds are about 1 eV, as predicted by all the three functionals. Since it is noted that GGA-PBE functional is most favourable for predicting structural properties and the energetic stability of ZrCoSb and ZrCoBi compounds, it is further used to calculate their thermoelectric properties. Within the energy range of 0-40 eV, the refractive index, dielectric constant, and energy loss function of ZrCoSb and ZrCoBi compounds are calculated. The possibility of electronic transition from the valence band maximum (VBM) to the conduction minimum band (CBM) is confirmed by the occurrence of absorption peaks in the visible range. For the evaluation of thermoelectric properties, the p-type and n-type doping attained Seebeck coefficients of 1800 and -1800 μVK at 300 K, respectively. The maximum peak of 17 × 10 W/m s K is attained in n-type doping, according to the power factor results.
在本研究中，展示了使用第一性原理计算得到的立方半赫斯勒化合物ZrCoY（Y为Sb和Bi）的结构、电子、力学、光学和热电性能。采用了以下交换关联泛函：佩德韦-伯克-恩泽尔霍夫广义梯度近似（GGA-PBE）、用于固体的佩德韦-伯克-恩泽尔霍夫广义梯度近似（GGA-PBESol）和局域密度近似（LDA）。基于弹性和声子性质分析，ZrCoSb和ZrCoBi化合物在力学和动力学上都是稳定的。如所有这三种泛函所预测的，这两种化合物计算得到的电子带隙约为1 eV。由于注意到GGA-PBE泛函最有利于预测ZrCoSb和ZrCoBi化合物的结构性质和能量稳定性，因此进一步用它来计算它们的热电性能。在0 - 40 eV的能量范围内，计算了ZrCoSb和ZrCoBi化合物的折射率、介电常数和能量损失函数。价带最大值（VBM）到导带最小值（CBM）的电子跃迁可能性通过可见光范围内吸收峰的出现得到证实。为了评估热电性能，p型和n型掺杂在300 K时分别获得了1800和 -1800 μVK的塞贝克系数。根据功率因子结果，n型掺杂中获得了17×10 W/m s K的最大峰值。
