一种用于热电应用的 LiCdSb 晶格热导率的 DFT 和机器学习辅助研究
A DFT and Machine Learning-Assisted Study on the Lattice Thermal Conductivity of LiCdSb for Thermoelectric Applications
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中文总结 AI 辅助
研究 LiCdSb 晶格热导率，采用 DFT 和玻尔兹曼输运方程计算其电子和热电性质，用 HSE06 计算带隙，因晶格热导率理论计算复杂，选用机器学习原子间势方法计算，结果与现有数据相符，高温下 ZT 值超 1，使其有望用于高温能量转换。
中文摘要 AI 辅助
通过使用第一性原理密度泛函理论（DFT）和玻尔兹曼输运方程，计算了 LiCdSb 的相应电子和热电性质。计算电子输运性质时，准确的能带结构估计至关重要，为此采用了高精度的 HSE06 混合泛函计算带隙。评估材料热电性能时，晶格热导率（Kl）计算是关键参数，但理论计算复杂且需大量计算资源，所以选用机器学习原子间势（MLIPs）方法计算 Kl。室温下 Kl = 0.24 Wm^-1K^-1 的结果与现有理论和实验数据定性相符。300K 时，基于 Slack + TDEC ZT 估计 Kl 得到的优值（ZT）为 0.18，机器学习（ML）模型 ZT 为 0.17，结合基于 HSE06 的电子输运性质与实验报道的 300K 时 ZT = 0.10 相符。600K 以上 ZT 值远高于基准值 1，这使 LiCdSb 成为高温能量转换的有前景材料。
英文摘要
By using first-principles density functional theory (DFT) and the Boltzmann transport equation, we have calculated the corresponding electronic and thermoelectric properties of LiCdSb. For calculating electron transport properties, accurate band-structure estimation is crucial. Hence, for the precise band gap calculation, we have implemented a hybrid functional HSE06, which is widely known for its high accuracy. To evaluate the thermoelectric performance of a material, the calculation of lattice thermal conductivity (Kl) is a key parameter. However, from a theoretical perspective, the calculation of lattice thermal conductivity is very complex and demands huge computational resources. Therefore, in this work, we have opted for an alternative method of machine-learning interatomic potentials (MLIPs) for the calculation of Kl. Our result of Kl=0.24 Wm^-1K^-1 at room temperature is in qualitative agreement with the available theoretical and experimental data. The figure of merit (ZT) with Kl estimated from Slack+TDEC ZT is 0.18 at 300 K, and machine learning (ML) models ZT is 0.17 at 300K, combining with HSE06-based electronic transport properties agreed well with the available experimentally reported value of ZT is 0.10 at 300K. However, we report the ZT value well above the benchmark value of 1 beyond 600K. The ZT value exceeding 1 at higher temperatures makes LiCdSb a promising material for high-temperature energy conversion.
