npj: 热导率的计算——天堑变通途

From npj 知社学术圈 2019-03-29

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晶格热导率是材料的重要属性，有着广泛用途，是确定热电材料能量转换效率的一个关键参数。然而，准确计算热导率涉及很大的计算量，耗时、费钱，成为相关高通量计算的瓶颈。现在，来自德国亚琛的Guangzhao Qin和Ming Hu提出了一种加速热导率计算的方法，即通过确定原子间相互作用的截断半径，找出必须计算区间，从而使计算速度提升近一个数量级。按他们的研究结果，将声子玻尔兹曼输运方程（BTE）与第一性原理计算相结合，能显著提高许多材料的晶格热导率计算速度。他们用此方法确定了石墨烯、磷烯及SnSe块体材料的晶格热导率。该方法可为材料的高通量筛选和热输运性能的设计提供基础。

该文近期发表于npj Computational Materials 4: 3 (2018); doi: 10.1038/s41524-017-0058-3。英文标题与摘要如下，点击阅读原文可以自由获取论文PDF。

Accelerating evaluation of converged lattice thermal conductivity

Guangzhao Qin & Ming Hu

Abstract High-throughput computational materials design is an emerging area in materials science, whichis based on the fast evaluation of physical-related properties. The latticethermal conductivity (κ) is a key property of materials for enormous implications. However, the high-throughput evaluation of κ remains a challenge due to the large resources costs and time-consuming procedures. In this paper, we propose a concise strategy to efficiently accelerate the evaluation process of obtaining accurate and converged κ. The strategy is in the framework of phonon Boltzmann transport equation (BTE) coupled with first-principles calculations. Based on the analysis of harmonic interatomic force constants (IFCs), the large enough cutoff radius (r^cutoff) , a critical parameter involved in calculating the anharmonic IFCs, can bedirectly determined to get satisfactory results. Moreover, we find a simple wayto largely (~10 times) accelerate the computations by fast reconstructing the anharmonic IFCs in the convergence test of κ with respect to the r^cutof, which finally confirms the chosen r^cutoff is appropriate. Two-dimensional graphene and phosphorene along with bulk SnSe are presented to validate our approach, and the long-debate divergence problem of thermal conductivity in low-dimensional systems is studied. The quantitative strategy proposed here in can be a good candidate for fast evaluating the reliable κ and thus provides useful tool for high-throughput materials screening and design with targeted thermal transport properties.