Journal of Materiomics ( IF 8.4 ) Pub Date : 2020-12-16 , DOI: 10.1016/j.jmat.2020.12.003 Qingyu Bai , Xinyue Zhang , Bing Shan , Xuemin Shi , Cheng Sun , Siqi Lin , Wen Li , Yanzhong Pei
Intrinsic partial occupation of Cu induces strong phonon scattering for an extremely low lattice thermal conductivity in TmCuTe2, which leads this material to be a promising candidate for thermoelectric applications. This work focus on the electronic and phononic transport properties of TmCuTe2 with Ag-alloying on the Cu site. Such a Ag/Cu substitution is found to enable a decrease in Hall carrier concentration from 14 × 1019 to 8 × 1019 cm−3 for an evaluation of the charge transport based on a single parabolic band (SPB) model with acoustic scattering. In addition, Ag-substitution simultaneously introduces Cu/Ag point defects for extra phonon scattering, leading the lattice thermal conductivity to be as low as ∼0.25 W/m-K in a broad temperature. The optimization in carrier concentration and the reduction in lattice thermal conductivity contribute to a ∼40% improvement in average thermoelectric figure of merit (zT). The determination of band parameters enables a guidance for further advancements in this promising thermoelectric material.
中文翻译:
TmAg x Cu 1- x Te 2固溶体的热电输运性质
Cu的本征部分会引起强声子散射,从而使TmCuTe 2中的晶格导热率极低,这导致该材料成为热电应用的有希望的候选者。这项工作的重点是在Cu部位采用Ag合金化的TmCuTe 2的电子和声子输运性质。发现这种Ag / Cu取代能够使霍尔载流子浓度从14×10 19降低至8×10 19 cm -3。用于基于带有声散射的单抛物线带(SPB)模型的电荷传输评估。另外,Ag替代同时引入Cu / Ag点缺陷以引起额外的声子散射,从而导致在较宽的温度下晶格热导率低至约0.25 W / mK。载流子浓度的优化和晶格热导率的降低有助于将平均热电品质因数(zT)提高约40%。带参数的确定为该有前途的热电材料的进一步发展提供了指导。