Effects of Rattling Behavior of K and Cd Atoms along Different Directions in Anisotropic KCdAs on Lattice Thermal Transport and Thermoelectric Properties  

作　　者：Yue Wang Yinchang Zhao Jun Ni Zhenhong Dai 

机构地区：[1]Department of Physics,Yantai University,Yantai 264005,China [2]State Key Laboratory of Low-Dimensional Quantum Physics,Department of Physics,Tsinghua University,Beijing 100084,China

出　　处：《Energy & Environmental Materials》2024年第6期388-398,共11页能源与环境材料（英文）

基　　金：supported by the Natural Science Foundation of Shandong Province for Major Basic Research under Grant No.ZR2023ZD09;the National Natural Science Foundation of China under Grant Nos.12174327,11974302,and 92270104.

摘　　要：We employ advanced first principles methodology,merging self-consistent phonon theory and the Boltzmann transport equation,to comprehensively explore the thermal transport and thermoelectric properties of KCdAs.Notably,the study accounts for the impact of quartic anharmonicity on phonon group velocities in the pursuit of lattice thermal conductivity and investigates 3ph and 4ph scattering processes on phonon lifetimes.Through various methodologies,including examining atomic vibrational modes and analyzing 3ph and 4ph scattering processes,the article unveils microphysical mechanisms contributing to the lowκL within KCdAs.Key features include significant anisotropy in Cd atoms,pronounced anharmonicity in K atoms,and relative vibrations in non-equivalent As atomic layers.Cd atoms,situated between As layers,exhibit rattling modes and strong lattice anharmonicity,contributing to the observed lowκL.Remarkably flat bands near the valence band maximum translate into high PF,aligning with ultralowκL for exceptional thermoelectric performance.Under optimal temperature and carrier concentration doping,outstanding ZT values are achieved:4.25(a(b)-axis,p-type,3×10^(19)cm^(−3),500 K),0.90(c-axis,p-type,5×10^(20)cm^(−3),700 K),1.61(a(b)-axis,n-type,2×10^(18)cm^(−3),700 K),and 3.06(c-axis,n-type,9×10^(17)cm^(−3),700 K).

关 键 词：anharmonic lattice dynamics electron transport characteristics first principles calculation lattice thermal transport OCTAHEDRON thermoelectric properties 

分 类 号：TB34[一般工业技术—材料科学与工程]