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

Abstract

Here we report the structural and electronic properties of CeAu${}_2$Bi, a new heavy-fermion compound crystallizing in a nonsymmorphic hexagonal structure ($P63/mmc$). 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 $|j_z=\pm 1/2⟩$ 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

7 pages, 5 figures. Supplemental Material: 4 pages, 2 figures

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• Superconductivity in the elements, alloys and simple compounds
• Möbius topological superconductivity in UPt${}_3$