Institute of Solid State Physics, Technische Universität Wien, Vienna, Austria.
Christian Doppler Laboratory for Thermoelectricity, Technische Universität Wien, Vienna, Austria.
Nature. 2019 Dec;576(7785):85-90. doi: 10.1038/s41586-019-1751-9. Epub 2019 Nov 13.
Thermoelectric materials transform a thermal gradient into electricity. The efficiency of this process relies on three material-dependent parameters: the Seebeck coefficient, the electrical resistivity and the thermal conductivity, summarized in the thermoelectric figure of merit. A large figure of merit is beneficial for potential applications such as thermoelectric generators. Here we report the thermal and electronic properties of thin-film Heusler alloys based on FeVWAl prepared by magnetron sputtering. Density functional theory calculations suggest that the thin films are metastable states, and measurements of the power factor-the ratio of the Seebeck coefficient squared divided by the electrical resistivity-suggest a high intrinsic figure of merit for these thin films. This may arise from a large differential density of states at the Fermi level and a Weyl-like electron dispersion close to the Fermi level, which indicates a high mobility of charge carriers owing to linear crossing in the electronic bands.
热电材料将温度梯度转化为电能。这个过程的效率取决于三个依赖于材料的参数：塞贝克系数、电阻率和热导率，它们综合在热电优值中。较大的优值有利于潜在的应用，如热电发电机。在这里，我们报告了通过磁控溅射制备的基于 FeVWAl 的薄膜 Heusler 合金的热和电子性能。密度泛函理论计算表明，薄膜处于亚稳态，功率因子（塞贝克系数平方与电阻率之比）的测量表明这些薄膜具有很高的固有优值。这可能是由于费米能级附近的差分态密度较大和类似 Weyl 的电子色散，这表明由于电子能带的线性交叉，载流子的迁移率较高。
