Large Room Temperature Anomalous Transverse Thermoelectric Effect in Kagome Antiferromagnet YMn₆ Sn₆

Kagome magnets possess several novel nontrivial topological features owing to the strong correlation between topology and magnetism that extends to their applications in the field of thermoelectricity. Conventional thermoelectric (TE) devices use the Seebeck effect to convert heat into electrical energy. In contrast, transverse thermoelectric devices based on the Nernst effect are attracting recent attention due to their unique transverse geometry, which uses a single material to eliminate the need for a multitude of electrical connections compared to conventional TE devices. Here, a large anomalous transverse thermoelectric effect of ≈2 µV K^-1 at room temperature in a kagome antiferromagnet YMn₆ Sn₆ single crystal is obtained. The obtained value is larger than that of state-of-the-art canted antiferromagnetic (AFM) materials and comparable with ferromagnetic systems. The large anomalous Nernst effect (ANE) can be attributed to the net Berry curvature near the Fermi level. Furthermore, the ANE of the AFM YMn₆ Sn₆ exceeds the magnetization scaling relationship of conventional ferromagnets. The results clearly illustrate that AFM material YMn₆ Sn₆ is an ideal topological material for room-temperature transverse thermoelectric applications.