Ce$_{ 3}$Bi$_{ 4}$Au$_{ 3}$ crystallizes in the same non-centrosymmetric cubic structure as the prototypical Kondo insulator Ce$_{ 3}$Bi$_{ 4}$Pt$_{ 3}$. Here we report the physical properties of Ce$_{ 3}$Bi$_{ 4}$Au$_{ 3}$ single crystals using magnetization, thermodynamic, and electrical-transport measurements. Magnetic-susceptibility and heat-capacity data reveal antiferromagnetic (AFM) order below $T_N=3.2$ K. The magnetic entropy $S_{ \rm mag}$ reaches $R$ln2 slightly above $T_N$, which suggests localized $4f$-moments in a doublet ground state. Multiple field-induced magnetic transitions are observed at temperatures below $T_N$, which indicate a complex spin structure with competing interactions. Ce$_{ 3}$Bi$_{ 4}$Au$_{ 3}$ shows semimetallic behavior in electrical resistivity measurements in contrast to the majority of reported Cerium-based 343 compounds. Electrical-resistivity measurements under hydrostatic pressure reveal a slight enhancement of $T_N$ under pressures up to 2.3 GPa, which supports a scenario wherein Ce$_{ 3}$Bi$_{ 4}$Au$_{ 3}$ belongs to the far left of the Doniach phase diagram dominated by Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions. Using realistic many-body simulations, we confirm the semi-metallic electronic structure of Ce$_{ 3}$Bi$_{ 4}$Au$_{ 3}$ and quantitatively reproduce its local moment behavior in the paramagnetic state.
Categories: cond-mat.str-el cond-mat.mtrl-sci