Experimental and first-principles studies of superconductivity in topological nodal line semimetal SnTaS$_2$

TL;DR

This study combines experimental measurements and first-principles calculations to explore superconductivity in SnTaS$_2$, revealing its potential as a 3D topological superconductor with nodal line features.

Contribution

It provides the first detailed experimental and theoretical investigation of superconductivity and topological properties in SnTaS$_2$, highlighting its nodal line topology and superconducting characteristics.

Findings

SnTaS$_2$ is a weakly coupled, type-II superconductor with T_c ≈ 2.8 K.

Electronic structure shows nodal line topology protected by symmetries.

Spin-orbit coupling gaps out the nodal lines, affecting topological features.

Abstract

We report a detailed study of superconductivity in polycrystalline SnTaS$_2$ using electrical transport, magnetization and heat capacity measurements. SnTaS$_2$ crystallizes in centrosymmetric hexagonal structure with space group $P6_3/mmc$. Electrical resistivity, magnetization and specific heat data suggest SnTaS$_2$ to be a weakly coupled, type-II superconductor with $T_c \approx$ 2.8 K. First-principles calculations show signature for nodal line topology in the electronic band structure, protected by the spatial-inversion and time-reversal symmetries, that strongly gapped out by the inclusion of spin-orbit coupling (SOC). Superconductivity in layered SnTaS$_2$ with nodal line topological state makes it a strong candidate to be considered for a 3D topological superconductor.