# Superconducting properties in a candidate topological nodal line semimetal SnTaS$_2$ with a centrosymmetric crystal structure

## TL;DR

This study investigates SnTaS$_2$, a layered superconductor with potential topological nodal line semimetal properties, revealing its superconducting behavior, anisotropic critical fields, and topological band crossings.

## Contribution

It provides the first combined experimental and theoretical analysis of SnTaS$_2$'s superconductivity and topological electronic structure, highlighting its possible topological nodal line semimetal nature.

## Key findings

- SnTaS$_2$ is a type-II superconductor with $T_c=3$ K.
- The upper critical field shows large anisotropy and unconventional temperature dependence.
- Band structure reveals nodal lines and drumhead surface states near the Fermi level.

## Abstract

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