CeAu${}_2$Bi: a new nonsymmorphic antiferromagnetic compound

Here we report the structural and electronic properties of CeAu${}_2$Bi, a new heavy-fermion compound crystallizing in a nonsymmorphic hexagonal structure ($P63\mathrm{/}mmc$). The Ce${}^{3+}$ ions form a triangular lattice which orders antiferromagnetically below $T_N=3.1$~K with a magnetic hard axis along the c-axis. Under applied pressure, $T_N$ increases linearly at a rate of $0.07$~K/kbar, indicating that the Ce $f$-electrons are fairly localized. In fact, heat capacity measurements provide an estimate of 150(10) mJ/mol.K${}^2$ for the Sommerfeld coefficient. The crystal-field scheme obtained from our thermodynamic data points to a ground state with dominantly $\mathrm{\mid }{j}_z=\pm 1\mathrm{/}2⟩$ character, which commonly occurs in systems with a hard c-axis. Finally, electronic band structure calculations and symmetry analysis in $k$-space reveal that CeAu${}_2$Bi hosts symmetry-protected crossings at $k_z=\pi$ in the paramagnetic state