Superconductivity in the nonsymmorphic line-nodal compound CaSb2

We found superconductivity in CaSb$_2$ with the transition temperature of 1.7 K by means of electrical-resistivity, magnetic-susceptibility, and specific-heat measurements. This material crystallizes in a nonsymmorphic structure and is predicted to have multiple Dirac nodal lines in the bulk electronic band structure protected by symmetry even in the presence of spin-orbit coupling. We discuss a possible topological superconductivity for the quasi-2-dimensional band originating mainly from one of the antimony sites.