Charge Balanced Vacancy Engineering to Enhance the Thermoelectric Properties of GeMnTe<sub>2</sub>
Lei Gao, Wenhao Li, Sitong Wei, Xinyue Yang, Zhen Ji, Weiyu Song, Shuqi Zheng
Abstract
As a derivative of GeTe and MnTe, GeMnTe 2 exhibits a cubic structure with no phase transition. Compared to GeTe, it is considerably cheaper and has a significantly high carrier concentration compared to MnTe, making it an excellent thermoelectric (TE) material with promising applications. Herein, a charge‐balanced vacancy engineering strategy is employed, resulting in a significant improvement in the power factor of GeMnTe 2 . Furthermore, the density functional theory calculation shows that the doping of Bi and the absence of Ge synergically increase the density of states near the Fermi level. Power factors of ≈13.7 μW cm −1 K −2 are achieved at 8% Bi content, a 22% improvement compared to the undoped system, while a final maximum ZT value of about 1.12 and an average ZT value of 0.72 are achieved. This indicates that charge‐balance vacancy engineering is an effective optimization method for the GeMnTe 2 system, which can effectively improve the TE performance.