Yang Jianhui, Fan Qiang, Cheng Xinlu
School of Physics and Electronic Engineering, Leshan Normal University, Leshan 614004, People's Republic of China.
Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, People's Republic of China.
R Soc Open Sci. 2017 Oct 4;4(10):170750. doi: 10.1098/rsos.170750. eCollection 2017 Oct.
The electronic, vibrational and thermoelectric transport characteristics of AgInTe and AgGaTe with chalcopyrite structure have been investigated. The electronic structures are calculated using the density-functional theory within the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof functional considering the Hubbard-U exchange correlation. The band-gaps of AgInTe and AgGaTe are much larger than previous standard GGA functional results and agree well with the existing experimental data. The effective mass of the hole and the shape of density of states near the edge of the valence band indicate AgInTe and AgGaTe are considerable p-type thermoelectric materials. An analysis of lattice dynamics shows the low thermal conductivities of AgInTe and AgGaTe. The thermoelectric transport properties' dependence on carrier concentration for p-type AgInTe and AgGaTe in a wide range of temperatures has been studied in detail. The results show that p-type AgInTe and AgGaTe at 800 K can achieve the merit values of 0.91 and 1.38 at about 2.12 × 10 cm and 1.97 × 10 cm carrier concentrations, respectively. This indicates p-type AgGaTe is a potential thermoelectric material at high temperature.
对具有黄铜矿结构的AgInTe和AgGaTe的电子、振动及热电输运特性进行了研究。采用密度泛函理论，在Perdew-Burke-Ernzerhof泛函的广义梯度近似（GGA）下，并考虑哈伯德U型交换关联，计算了其电子结构。AgInTe和AgGaTe的带隙比之前标准GGA泛函的结果大得多，且与现有的实验数据吻合良好。空穴的有效质量以及价带边缘附近的态密度形状表明，AgInTe和AgGaTe是相当不错的p型热电材料。晶格动力学分析表明，AgInTe和AgGaTe的热导率较低。详细研究了在较宽温度范围内，p型AgInTe和AgGaTe的热电输运性质对载流子浓度的依赖性。结果表明，在800 K时，p型AgInTe和AgGaTe在载流子浓度分别约为2.12×10 cm和1.97×10 cm时，优值分别可达0.91和1.38。这表明p型AgGaTe是一种潜在的高温热电材料。
