Large room-temperature anomalous Nernst effect in a metallic square-net ferromagnet SmMn2Ge2 single crystal

Abstract

In a ferromagnet, heat current can generate a transverse electric voltage orthogonal to its magnetization, known as the anomalous Nernst effect (ANE). It shows technical advantages over the conventional longitudinal Seebeck effect owing to its transverse geometry. However, materials with large (above) room-temperature ANE remain to be explored. Here, a metallic square-net ferromagnet SmMn2Ge2 single crystal was synthesized, and its ANE was investigated through comprehensive magnetic, electrical, and thermal transport measurements. At room temperature, SmMn2Ge2 exhibits a significant ANE with a large anomalous Nernst signal (Syx A) ∼ 1.04 μV/K, anomalous Nernst angle ∼ 11%, and anomalous transverse thermoelectric figure of merit (zTANE) ∼ 5 × 10−5. The scaling analyses of the anomalous Hall conductivity and anomalous Nernst conductivity indicate that the origin of anomalous transverse transports in SmMn2Ge2 is dominated by the intrinsic Berry curvature. The large ANE in SmMn2Ge2 at room temperature makes it a promising candidate for transverse thermoelectric devices.