Design of anomalous Nernst thermoelectric generators for giant power output.

Abstract

Topological magnets have shown great potential for transverse thermoelectric (TE) conversion with structural advantages, utilizing the anomalous Nernst effect. To facilitate such applications, the development of exceptional topological magnet-based Nernst devices is a crucial step that requires both high-performance topological magnets and the design of low-resistance interfaces in the devices. Here, we report that the anomalous Nernst effect in topological magnets can be ubiquitously enhanced by synergistically tuning the entropy-density-weighted Berry curvature and the Fermi surface, as evidenced by a giant anomalous Nernst power factor of 47.8 μW m^-1 K^-2 at room temperature in electron-doped Co₂MnGa. In addition, we achieved an ultralow interfacial resistivity in the Nernst device by designing reactive wetting interfacial layers, enabling an ultrahigh power output of 69.7 μW at a temperature difference of 16.1 K, the highest value yet reported to date. We have also experimentally corroborated the structural advantages of transverse TE technology by developing Nernst devices with different length-to-thickness ratios. Our work demonstrates a paradigm for designing exceptional topological magnet-based Nernst generators for transverse TE conversion.