Npj Comput. Mater.: 形变势的高通量计算
海归学者发起的公益学术平台
分享信息，整合资源
交流学术，偶尔风月
热电材料性能优化的关键是提高热电输运性能。弛豫时间计算一直是电输运性能计算的难点和关键，由于电子-声子相互作用，精确电声计算对复杂热电材料是一个挑战。精确的电声计算虽然能够给出精确的弛豫时间结果，然而由于其电-声散射的复杂性，其计算量较大，难以在复杂材料体系中实现，常数弛豫时间近似方法作为一种常用的电输运计算方法，其精确性值得商榷。高效可靠的电子弛豫时间计算方法对材料电输运性能的计算和预测至关重要。基于常数电声耦合近似的形变势方法则是一种兼顾计算成本和精确性的电子弛豫时间近似方法，对快速准确预测新型高性能热电材料具有重要的意义。
图1：形变势及电输运性能高通量计算流程图
上海大学材料基因组工程研究院的杨炯教授和席丽丽副研究员基于前期JACS工作中电声耦合近似的形变势方法进行改进，建立了适用于高通量计算的形变势方法，其计算流程如图1所示。形变势高通量处理中能带对齐方式选用第一条能带平均值为基准，避免了复杂化合物中不同元素芯能级为基准的不确定性，获得了1万多条形变势数据及电输运性能。并通过高通量预测出332种潜在的n型热电材料和321种p型热电材料，最终获得156种潜在的n型、p型性能均优异的新型高性能热电材料。本工作提出的高通量形变势处理方法，获得了大量形变势数据及电输运性能参数，可以系统分析形变势的分布规律及影响因素，还获得了形变势与电输运性能的关系（图2），对加速高性能材料的发现具有重要的意义，同时也为进一步的机器学习研究提供了大量的数据支持。
图2 热电材料的电输运性能功率因子分布及其与形变势常数的关系、高通量热电材料筛选
该文近期发表于npj Computational Materials 9,: 190 (2023)，英文标题与摘要如下，点击左下角“阅读原文”可以自由获取论文PDF。
High-throughput deformation potential and electrical transport calculations
Yeqing Jin, Xiangdong Wang, Mingjia Yao, Di Qiu, David J. Singh, Jinyang Xi, Jiong Yang, & Lili Xi
The deformation potential plays an important role in electrical transport properties, but in the context of high-throughput searches requires a consistent and readily computable reference level. Here, we design a high-throughput method for calculating the deformation potential for semiconductors in the MatHub-3d database. The deformation potential is obtained from the volume-dependent band edge (valence band maximum and conduction band minimum) variations with respect to the reference level. In order to adapt the calculation of reference level to a high-throughput manner, the average value of the first valence electron energy band associated with each compound is used as the reference level. Deformation potentials for 11,993 materials are calculated using the above-mentioned method. By considering the calculated deformation potentials, electronic structures, and bulk moduli, 9957 compounds with converged electrical transport properties are obtained. 332 promising p-type thermoelectric materials, and 321 n-type entries are then proposed. Among them, 156 compounds are screened to having both potentially good n- and p-type thermoelectric transport properties. The band structures and chemical bonding information for several typical compounds are further presented to reveal favorable band and bonding features for thermoelectrics.
扩展阅读
微信扫码关注该文公众号作者