Large Anomalous and Topological Hall Effect and Nernst Effect in a Dirac Kagome Magnet Fe₃Ge

Searching for Kagome magnets with novel magnetic and electronic properties has been attracting significant efforts recently. Here, the magnetic, electronic, and thermoelectric properties of Fe₃Ge single crystals with Fe atoms forming a slightly distorted Kagome lattice are reported. It is shown that Fe₃Ge exhibits a large anomalous Hall effect and anomalous Nernst effect. The observed anomalous transverse thermoelectric conductivity (Formula presented.) reaches ≈4.6 A m⁻¹ K⁻¹, which is larger than the conventional ferromagnets and most of the topological ferromagnets reported in literature. The first-principles calculations suggest that these exceptional transport properties are dominated by the intrinsic mechanism, which highlights the significant contribution of the Berry curvature of massive Dirac gaps in the momentum space. Additionally, a topological Hall resistivity of 0.9 µΩ cm and a topological Nernst coefficient of 1.2 µV K⁻¹ are also observed, which are presumably ascribed to the Berry phase associated with the field-induced non-zero scalar spin chirality. These features highlight the synergic effects of the Berry phases in both momentum space and real space of Fe₃Ge, which render it an excellent candidate for room-temperature thermoelectric applications based on transverse transport.