Yang Gui, Yang Jueming, Yan Yuli, Wang Yuanxu
Institute for Computational Materials Science, School of Physics and Electronics, Henan University, Kaifeng 475004, China.
Phys Chem Chem Phys. 2014 Mar 28;16(12):5661-6. doi: 10.1039/c3cp54545h. Epub 2014 Feb 12.
The electronic structure and the thermoelectric properties of M2Zn5As4 (M = K, Rb) are studied by the first principles and the semiclassical BoltzTraP theory. It is determined that they are semiconductors with an indirect band gap of about 1 eV, which is much larger than that of Ca5Al2Sb6 (0.50 eV). The calculated electronic localization function indicates that they are typical Zintl bonding compounds. The combination of heavy and light bands near the valence band maximum may improve their thermoelectric performance. Rb2Zn5As4 exhibits relatively large Seebeck coefficients, high electrical conductivities, and the large "maximum" thermoelectric figures of merit (ZeT). Compared with Ca5Al2Sb6, the highest ZeT of Rb2Zn5As4 appears at relatively low carrier concentration. For Rb2Zn4As5, the p-type doping may achieve a higher thermoelectric performance than n-type doping. The thermoelectric properties of Rb2Zn5As4 are possibly superior to those of Ca5Al2Sb6.
采用第一性原理和半经典玻尔兹曼输运理论研究了M2Zn5As4（M = K，Rb）的电子结构和热电性能。确定它们是间接带隙约为1 eV的半导体，这比Ca5Al2Sb6（0.50 eV）的带隙大得多。计算得到的电子局域函数表明它们是典型的津特耳键合化合物。价带最大值附近重带和轻带的组合可能会改善它们的热电性能。Rb2Zn5As4表现出相对较大的塞贝克系数、高电导率以及较大的“最大”热电优值（泽贝克系数乘以温度除以热导率，ZeT）。与Ca5Al2Sb6相比，Rb2Zn5As4的最高泽贝克系数出现在相对较低的载流子浓度下。对于Rb2Zn4As5，p型掺杂可能比n型掺杂具有更高的热电性能。Rb2Zn5As4的热电性能可能优于Ca5Al2Sb6。
