层状化合物PbSnS_(2)热电输运性质的第一性原理计算研究  

Investigation of thermoelectric properties in layered PbSnS_(2)from first-principles calculations

作　　者：王东洋[1] 李晓东[1] 朱佳琪 赵珂[1] 程少博[1] Dongyang Wang;Xiaodong Li;Jiaqi Zhu;Ke Zhao;Shaobo Cheng(Key Laboratory of Materials Physics of Ministry of Education,School of Physics,Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]郑州大学物理学院,材料物理教育部重点实验室,郑州450001

出　　处：《科学通报》2025年第6期746-754,共9页Chinese Science Bulletin

基　　金：国家自然科学基金(12204156,62271450);中国博士后科学基金(2023TQ0315,2023M743224);国家超级计算郑州中心资助。

摘　　要：本文基于第一性原理计算与Boltzmann输运理论研究了层状化合物PbSnS_(2)的热电输运性质.结果表明,PbSnS_(2)的本征低热导率归因于Pb/Sn–S成键的多样性和Pb/Sn的孤对电子所带来的强非简谐性.导带底尖锐的带边结构有利于获得高迁移率,较平坦的价带有助于获得高塞贝克系数,导致了输运性质的各向异性.最终n型PbSnS_(2)面外方向的峰值ZT在900 K时达到2.81.对于p型掺杂,面内方向的峰值ZT在900 K时达到1.05.本研究揭示了PbSnS_(2)的本征低热导率机制,预测了其各向异性的热电输运性能,为PbSnS_(2)基材料热电性能的进一步优化提供了理论指导,相关结果有待实验的验证.Thermoelectric materials are solid-state materials that can convert thermal energy into electrical energy and vice versa.In recent years,there has been significant progress in the development of advanced thermoelectric materials with improved efficiency and cost-effectiveness.To date,high figure-of-merit was obtained in n-type and p-type SnSe,providing a solid foundation for the construction of thermoelectric devices.The low cost and environmentally friendly SnS,an analogue of SnSe,has also been greatly developed and a high average ZT of 1.25 was reported in p-type SnS0.91Se0.09 crystals.However,the thermoelectric performance of n-type SnS is far lagging due to the great difficulties and challenges on achieving effective electron doping to optimize the poor n-type electrical transports.A novel sulfide compound,PbSnS_(2),is isostructural to SnS and exhibits promising n-type thermoelectric performance due to its intrinsically low thermal conductivity.The PbSnS_(1.96)Cl_(0.04)crystal exhibits a ZT_(max)of~1.20 at 773 K and a ZT_(ave)of~0.79 within the temperature range of 300–823 K,specifically along out-of-plane directions.In contrast,along the in-plane direction,a record-high ZT value of~1.20 was achieved at 473 K.However,this performance is still unsatisfactory for the realization of low-cost and high-efficiency thermoelectric devices with p-type SnS.In this work,we investigate the thermoelectric properties of PbSnS_(2)compounds based on first-principles calculations and Boltzmann transport theory.The results show that the intrinsically low thermal conductivity of PbSnS_(2)originates from the strong lattice anharmonicity since the multiple chemical bonding between Pb/Sn and S atoms,and the lone-pair electrons of Pb/Sn.The sharp band edge at the bottom of the conduction band is conducive to achieving high mobility,and the flatten valence band helps to obtain high Seebeck coefficients,leading to strong anisotropic transport properties.The doping can effectively improve the electrical transport through increasing

关 键 词：第一性原理计算 热电材料 PbSnS_(2) 晶格热导率 热电优值 

分 类 号：TB34[一般工业技术—材料科学与工程] O469[理学—凝聚态物理]