Transport and thermoelectric properties of U3As4

The discovery of materials with exceptionally large Anomalous Hall Angle (AHA) is both fundamentally significant and technologically relevant. Large AHA often originate from Berry curvature effects associated with nontrivial band topology, while also enabling efficient charge-to-spin conversion, enhanced Hall sensor sensitivity, and low-dissipation transport. Uranium compounds are promising candidates for realizing such responses due to their correlated 5f electrons, flat-band characteristics, and strong spin–orbit coupling, yet systematic studies remain limited. Here, we report on those properties of the uranium-based ferromagnet U₃As₄, a body-centered cubic compound with a Curie temperature of 198 K and heavy-fermion character (γ = 83 mJ/K²·mol). Remarkably, U₃As₄ exhibits a giant anomalous Hall angle of more than 40%, among the largest reported in ferromagnets, and an anomalous Hall conductivity comparable to Co2MnGa and surpassing many topological ferromagnets. The interplay of correlated 5f states, strong spin–orbit coupling, and possible topological band features drives these exceptional responses, establishing U₃As₄ as a fertile platform for exploring topological heavy-fermion physics and advancing spintronic and thermoelectric applications.