GeTe has been known as an excellent thermoelectrics, whereas its realistically application is limited by its structural phase transition near 700 K. Here, we show that the temperature of phase transition can be suppressed below 300 K by alloying 35% MnTe. The GeTe-MnTe alloy exhibits the much different transport properties from GeTe. Its room-temperature Seebeck coefficient is close to that of optimized GeTe, while its carrier concentration is one order higher. The increase of Seebeck coefficient of GeTe-MnTe is found to be accompanied with the decrease of magnetic susceptibility, while GeTe shows the opposite trend. By optimizing the carrier concentration with Bi doping and Bi/Sb co-doping, the peak figure of merit of GeTe-MnTe reaches 1.46 at 823 K. Our study reveals that GeTe-MnTe alloy is a novel and promising thermoelectric material.

中文翻译：

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自旋自由度驱动的GeTe-MnTe合金的高热电性能

GeTe 被认为是一种优异的热电材料，但其实际应用受到其在 700 K 附近的结构相变的限制。在这里，我们表明，通过合金化 35% MnTe 可以将相变温度抑制在 300 K 以下。 GeTe-MnTe 合金表现出与 GeTe 截然不同的输运特性。其室温塞贝克系数接近优化的GeTe，而载流子浓度则高出一个数量级。研究发现GeTe-MnTe的塞贝克系数增加伴随着磁化率的降低，而GeTe则表现出相反的趋势。通过优化 Bi 掺杂和 Bi/Sb 共掺杂的载流子浓度，GeTe-MnTe 的峰值品质因数在 823 K 时达到 1.46。我们的研究表明，GeTe-MnTe 合金是一种新型且有前途的热电材料。