Topological Nernst, Anomalous Nernst, and Anomalous Thermal Hall effect in the Kagome magnet YMn₆Sn₄Ge₂

RMn₆Sn₆ (R = rare earth elements) are magnetic compounds that form in a Kagome lattice structure. Among the family, YMn₆Sn₆ has attracted much interest, as it hosts multiple competing magnetic phases, magnetization driven Lifshitz transitions, Dirac points, flat bands, and anomalous Nernst and Hall effect. To study how the magnetic structures can be tuned by Ge substitution, YMn₆Sn₄Ge₂ has been recently synthesized and demonstrates distinct magnetic phases from the parent compound’s transverse conical spiral and fan-like phases. In this study, we performed thermal and thermoelectric measurements on YMn₆Sn₄Ge₂ to understand how transport properties can be affected by magnetic structures. We observed a topological Nernst effect, along with an anomalous Nernst and thermal Hall effect, which differs from the parent compound. Our study reveals the non-trivial topological nature of YMn₆Sn₄Ge₂ and the sensitivity of its magnetic structure to Ge-substitution.