Liton M N H, Farid Ul Islam A K M, Sarker M S I, Rahman M M, Khan M K R
Department of Physics, University of Rajshahi, Rajshahi, 6205, Bangladesh.
Department of Physics, Begum Rokeya University, Rangpur, Rangpur, 5400, Bangladesh.
Heliyon. 2024 Dec 18;11(1):e41220. doi: 10.1016/j.heliyon.2024.e41220. eCollection 2025 Jan 15.
The present study focuses on the ground state mechanical, acoustic, thermodynamic and electronic transport properties of NaSbS polymorphs using the density functional theory (DFT) and semi-classical Boltzmann transport theory. The mechanical stability of the polymorphs is affirmed by the calculated elastic tensor. The calculated elastic properties asserted that all the polymorphs exhibit soft, brittle, anisotropic nature containing dominant covalent bonding. The 2D polar graphs are used to describe the anisotropic characteristic of the elastic parameters. The estimated value of Young's modulus and lattice thermal conductivity suggested that the polymorphs could be suitable for thermal barrier coating. Heat capacity, melting temperature, thermal conductivities, Grüneisen parameter, and thermal expansion coefficient of the polymorphs have also been studied to demonstrate thermodynamic behavior. The predicted lower values of lattice thermal conductivity declared that NaSbS polymorphs exhibit excellent electrical conductivity and transport properties. The estimated Seebeck coefficient (S), power factor (PF) and figure of merit (ZT) suggested that n-type triclinic and monoclinic, as well as p-type trigonal NaSbS, are better for thermoelectric applications. The optimal carrier concentration for monoclinic structure is 10 cm for T < 750 K, while it becomes 10 cm for T > 750 K. It is also found that the optimal carrier concentration of the trigonal is 10 cm, whereas it is 10 cm for triclinic structures. Therefore, it can be stated that NaSbS2 polymorphs possess excellent thermoelectric features, making them a promising choice for thermoelectric (TE) applications.
本研究使用密度泛函理论（DFT）和半经典玻尔兹曼输运理论，聚焦于NaSbS多晶型物的基态力学、声学、热力学和电子输运性质。通过计算弹性张量确定了多晶型物的力学稳定性。计算得到的弹性性质表明，所有多晶型物均表现出柔软、脆性、各向异性的性质，且含有主导的共价键。二维极坐标图用于描述弹性参数的各向异性特征。杨氏模量和晶格热导率的估计值表明，这些多晶型物可能适用于热障涂层。还研究了多晶型物的热容、熔化温度、热导率、格林艾森参数和热膨胀系数，以展示其热力学行为。预测的较低晶格热导率值表明，NaSbS多晶型物具有优异的电导率和输运性质。估计的塞贝克系数（S）、功率因数（PF）和优值（ZT）表明，n型三斜和单斜以及p型三角NaSbS在热电应用方面表现更佳。单斜结构在T < 750 K时的最佳载流子浓度为10 cm，而在T > 750 K时变为10 cm。还发现三角结构的最佳载流子浓度为10 cm，而三斜结构为10 cm。因此，可以说NaSbS2多晶型物具有优异的热电特性，使其成为热电（TE）应用的一个有前景的选择。
