Abstract Thermoelectric materials are attracting increasing attention for their ability to convert heat into cleaner electricity. In this work, we have systematically studied the thermoelectric properties of strontium sulfide (SrS) in the rock-salt structure based on first-principle calculations together with Boltzmann transport theory. The phonon spectra of the rock-salt structure SrS have no imaginary frequency modes, indicating the dynamic stability of SrS. The room-temperature lattice thermal conductivity κι of SrS is calculated to be 10.70 W/mK. We also calculated the phonon-mode contribution to κι, scattering rate, and mean free path (MFP). It is found that the acoustic branches have obvious contribution to the total lattice thermal conductivity, and the MFP can provide guidance for designing thermoelectric nanostructures. The ZT values of SrS with respect to carrier concentration n and temperature T are also obtained. It is found that, when temperature is from 300 K to 700 K, for p-type, the highest ZT value calculated by PBE varies from 0.15 to 0.41, and the highest ZT value by HSE varies from 0.10 to 0.30; For n-type, the highest ZT value by PBE varies from 0.08 to 0.26, and the highest ZT value by HSE varies from 0.09 to 0.28. In general, the p-type SrS has the better thermoelectric property than the n-type SrS.

中文翻译：

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通过第一性原理计算硫化锶的热电性能

摘要 热电材料因其将热量转化为清洁电能的能力而越来越受到关注。在这项工作中，我们基于第一性原理计算结合玻尔兹曼输运理论系统地研究了岩盐结构中硫化锶 (SrS) 的热电性质。岩盐结构 SrS 的声子谱没有虚频模式，表明 SrS 的动态稳定性。SrS的室温晶格热导率κι经计算为10.70W/mK。我们还计算了声子模式对 κι、散射率和平均自由程 (MFP) 的贡献。发现声分支对总晶格热导率有明显贡献，MFP可以为设计热电纳米结构提供指导。还获得了 SrS 相对于载流子浓度 n 和温度 T 的 ZT 值。发现，当温度为300 K～700 K时，对于p型，PBE计算的最高ZT值为0.15～0.41，HSE计算的最高ZT值为0.10～0.30；对于 n 型，PBE 的最高 ZT 值从 0.08 到 0.26 不等，HSE 的最高 ZT 值从 0.09 到 0.28 不等。一般来说，p型SrS比n型SrS具有更好的热电性能。HSE 的最高 ZT 值在 0.09 到 0.28 之间变化。一般来说，p型SrS比n型SrS具有更好的热电性能。HSE 的最高 ZT 值在 0.09 到 0.28 之间变化。一般来说，p型SrS比n型SrS具有更好的热电性能。