Localized <i>f</i>-electron magnetism in the semimetal Ce₃Bi₄Au₃

Ce3Bi4Au3 crystallizes in the same noncentrosymmetric cubic structure as the prototypical Kondo insulator Ce3Bi4Pt3. Here we report the physical properties of Ce3Bi4Au3 single crystals using magnetization, thermodynamic, and electrical-transport measurements. Magnetic-susceptibility and heat-capacity data reveal antiferromagnetic order below TN=3.2K. The magnetic entropy Smag reaches Rln2 slightly above TN, which suggests localized 4f moments in a doublet ground state. Multiple field-induced magnetic transitions are observed at temperatures below TN, which indicate a complex spin structure with competing interactions. Ce3Bi4Au3 shows semimetallic behavior in electrical resistivity in contrast to the majority of reported cerium-based 343 compounds which are semiconducting. Electrical-resistivity measurements under hydrostatic pressure reveal a slight enhancement of TN under pressures up to 2.3 GPa, which supports a scenario wherein Ce3Bi4Au3 belongs to the far left of the Doniach phase diagram dominated by Ruderman-Kittel-Kasuya-Yosida interactions. Using realistic many-body simulations, we confirm the semimetallic electronic structure of Ce3Bi4Au3 and quantitatively reproduce its local moment behavior in the paramagnetic state.