We report the magnetization, the electrical resistivity, specific heat measurements, and band structure calculations of the layered superconductor ${\mathrm{SnTaS}}_2$. The experiments are performed on single crystals grown by the chemical vapor transport method. The resistivity and magnetic susceptibility indicate that ${\mathrm{SnTaS}}_2$ is a type-II superconductor with the transition temperature $T_c=3$ K. The upper critical field $\left(H_{c2}\right)$ shows large anisotropy for the magnetic field parallel to the $ab$ plane $\left(H//ab\right)$ and the $c$ axis $\left(H//c\right)$, and the temperature dependence of $H_{c2}$ for $H//ab$ shows an obvious unconventional upward feature at low temperature. The band structure of ${\mathrm{SnTaS}}_2$ shows several band crossings near the Fermi level, which form three nodal lines in the $k_z=0$ plane resulting in drumheadlike surface states when spin-orbit coupling is not considered. These results indicate that ${\mathrm{SnTaS}}_2$ is a superconductor with a possible topological nodal line semimetal character.

• Received 4 May 2019

DOI:https://doi.org/10.1103/PhysRevB.100.064516