Giant Anomalous Nernst Angle Induced by Berry Curvature in Layered Itinerant Ferromagnets

Berry curvature describes the intrinsic geometric property of electronic band structure, crucial for governing emergent transport phenomena. As a typical Berry-curvature-related property, the anomalous Nernst effect probes local Berry curvature near the Fermi surface, whereas the anomalous Hall effect integrates contributions across all occupied states. Thus, the anomalous Nernst effect is a superior probe for detecting subtle evolution of Berry curvature near the Fermi level; however, their relation remains elusive. Here, we demonstrate giant anomalous Nernst angles induced by Berry curvature in layered itinerant ferromagnets Fe_3GaTe_2 and Fe_5GeTe_2. Their maximum values (\approx,0.33 for Fe_3GaTe_2 and \approx,0.41 for Fe_5GeTe_2) are one order of magnitude larger than those of traditional ferromagnets (\theta_\rm AN^\max < 0.02). Scaling analysis of anomalous Hall effect in these two systems further suggests these giant angles originate from intrinsic Berry curvature. These findings indicate Berry-curvature-dominated regimes, and establish these materials for high-performance spin-caloritronic devices.