第一原理計算とワニエ模型に基づく磁気熱電材料の探索

抄録

Thermoelectric conversion using the anomalous Nernst effect (ANE) has excellent potential for application in energy harvesting technology. Compared to the typical thermoelectric effect known as the Seebeck effect, the thermoelectric figure of merit in ANE is about ten times smaller; material search with a large ANE response is a critical challenge aiming to achieve its application. In this study, we implement a high-throughput material search for evaluating ANE and perform this material screening up to 1400 magnets. We find that D03 type Heusler compound Fe3Ga shows 6 microvolts per kelvin at room temperature. Motivated by the recent discovery of a large ANE material, we also analyze the origin of the enhancement of ANE from the topological electronic structure. We find that not only the Weyl points but also stationary points in the energy dispersion of the nodal lines play a crucial role in enhancing ANE. These present results will give us a useful guiding principle to design magnets showing a large ANE.