High Temperature Thermoelectric Response of Electron-Doped CaMnO3
High Temperature Thermoelectric Response of Electron-Doped CaMnO3
复制标题
电子掺杂 CaMnO3 的高温热电响应
DOI：
10.1021/cm901766y
复制
发表时间：
2009-10-13
影响因子：
8.6
通讯作者：
Liu, Xiaoyang
中科院分区：
文献类型：
--
作者：
Wang, Yang;Sui, Yu;Liu, Xiaoyang
本文系统地研究了Ca_（1-x）R_xMnO_3（R =稀土）钙钛矿在电子掺杂范围内的高温热电响应。结果表明，电子浓度是高温电输运性质的主导因素，而R离子的质量和尺寸决定热输运性质。随着掺杂水平的变化，在相对电子浓度为0.1左右时观察到最佳的热电性能。然而，在电子浓度固定的情况下，结构畸变变得重要，因为带宽对电阻率具有可观察到的影响。综合考虑电子浓度、晶体结构和R离子的质量/尺寸这三个因素，在1000 K时，Ca 1-xRxMnO 3的最大热电优值ZT达到0.2。但该ZT值与应用标准（ZT > 1）仍相差甚远。使用动态平均场理论，我们表明，ZT值大于一个电子掺杂的CaMnO 3系统似乎是不太可能的。提出了在过渡金属氧化物中寻找高性能热电材料的策略。
We report a systematical investigation on the high temperature thermoelectric response of Ca1-xRxMnO3 (R = rare-earth) perovskites in the electron-doped range. The results reveal that electron concentration is the dominant factor for the high temperature electrical transport properties whereas the weight and size of R ions dominate the thermal transport properties. As the doping level varies, the best thermoelectric performance is observed at the relative electron concentration around 0.1. However, in the case of a fixed electron concentration, structural distortions become important since bandwidth has an observable influence on resistivity. By combining the three factors, electron concentration, crystal structure, and the weight/size of R ions, the largest thermoelectric figure of merit ZT for Ca1-xRxMnO3 reaches 0.2 at 1000 K. But this ZT value is still too far from the application criterion (ZT > 1). Using the dynamical mean field theory, we demonstrate that a ZT value larger than one in electron-doped CaMnO3 systems seems rather unlikely. Some strategies for searching new thermoelectric materials with high performance in transition metal oxides are proposed.