Superconducting properties in a candidate topological nodal line semimetal SnTaS2 with a centrosymmetric crystal structure

We report the magnetization, the electrical resistivity, specific heat measurements, and band structure calculations of the layered superconductor SnTaS2. The experiments are performed on single crystals grown by the chemical vapor transport method. The resistivity and magnetic susceptibility indicate that SnTaS2 is a type-II superconductor with the transition temperature Tc=3 K. The upper critical field (Hc2) shows large anisotropy for the magnetic field parallel to the ab plane (H//ab) and the c axis (H//c), and the temperature dependence of Hc2 for H//ab shows an obvious unconventional upward feature at low temperature. The band structure of SnTaS2 shows several band crossings near the Fermi level, which form three nodal lines in the kz=0 plane resulting in drumheadlike surface states when spin-orbit coupling is not considered. These results indicate that SnTaS2 is a superconductor with a possible topological nodal line semimetal character.