Superconductivity in BaPtSb with an Ordered Honeycomb Network

Superconductivity in BaPtSb with the SrPtSb-type structure (space group $P\bar{6}m2$, $D_{3h}^1$, No. 187) is reported. The structure consists of a PtSb ordered honeycomb network that stacks along the $c$-axis so that spatial inversion symmetry is broken globally. Electrical resistivity and specific-heat measurements revealed that the compound exhibited superconductivity at 1.64 K. The noncentrosymmetric structure and the strong spin-orbit coupling of Pt and Sb make BaPtSb an attractive compound for studying the exotic superconductivity predicted for a honeycomb network.