Islam Md Minhajul, Wróblewska Maria, Shen Zihao, Toberer Eric S, Taufour Valentin, Kauzlarich Susan M
Department of Chemistry, University of California, One Shields Ave, Davis, California 95616, United States.
Department of Physics, Colorado School of Mines, 1500 Illinois St, Golden, Colorado 80401, United States.
Chem Mater. 2024 Nov 22;36(23):11499-11508. doi: 10.1021/acs.chemmater.4c02200. eCollection 2024 Dec 10.
Compositional diversity and intriguing structural features have made Zintl phases excellent candidates as thermoelectric materials. Zintl phase with 21-4-18 composition has shown high thermoelectric performance in the mid- to high-temperature ranges. The complex crystal structure and favorable transport properties of these compounds indicate the potential for high thermoelectric efficiency. Arsenic-based EuZnAs, belonging to the CaMnSb structure type, exhibits a semiconductor-like p-type transport behavior and has a calculated band gap of 0.49 eV. The compound is paramagnetic at high temperatures, with an antiferromagnetic transition occurring at = ∼10 K. The moment obtained from the Curie-Weiss data fit aligns with Eu ions. At the same time, the field-dependent measurement at 2 K indicates complex magnetic ordering with a saturation moment consistent with Eu ions. Pristine EuZnAs exhibits an ultralow lattice thermal conductivity of 0.40 W m K at 873 K. Electronic transport properties measurement shows evidence of bipolar conduction across much of the measured temperature range (450-780 K). However, the Seebeck coefficient remains extremely high (>440 μV K) across this range, indicating the potential for high if an appropriate dopant is found. This work represents the first report on the temperature-dependent thermal conductivity, Seebeck coefficient, and thermoelectric efficiency of the arsenic-containing Zintl phase with 21-4-18 composition, showcasing its promise for further optimization of the thermoelectric performance.
组成多样性和引人入胜的结构特征使津特相成为热电材料的理想候选者。具有21-4-18组成的津特相在中高温范围内表现出高热电性能。这些化合物复杂的晶体结构和良好的输运性质表明其具有高热电效率的潜力。基于砷的EuZnAs属于CaMnSb结构类型，表现出类似半导体的p型输运行为，计算得到的带隙为0.49 eV。该化合物在高温下是顺磁性的，在T = ∼10 K时发生反铁磁转变。从居里-外斯数据拟合得到的磁矩与Eu离子一致。同时，在2 K下的磁场依赖性测量表明存在复杂的磁有序，其饱和磁矩与Eu离子一致。纯净的EuZnAs在873 K时表现出超低的晶格热导率，为0.40 W m K。电子输运性质测量表明，在大部分测量温度范围（450 - 780 K）内存在双极传导。然而，在此温度范围内塞贝克系数仍然极高（>440 μV K），这表明如果找到合适的掺杂剂，其具有高热电优值的潜力。这项工作首次报道了具有21-4-18组成的含砷津特相的温度依赖性热导率、塞贝克系数和热电效率，展示了其在进一步优化热电性能方面的前景。
