Nodeless superconductivity in the SnAs-based van der Waals type superconductor NaSn2As2

Abstract

We grew the single crystals of the SnAs-based van der Waals (vdW)-type superconductor NaSn${}_2$As${}_2$ and systematically measured its resistivity, specific heat, and ultralow-temperature thermal conductivity. The superconducting transition temperature $T_c$ = 1.60 K of our single crystal is 0.3 K higher than that previously reported. A weak but intrinsic anomaly situated at 193 K is observed in both resistivity and specific heat, which likely arises from a charge-density-wave (CDW) instability. Ultralow-temperature thermal conductivity measurements reveal a fully-gapped superconducting state with a negligible residual linear term in zero magnetic field, and the field dependence of ${\kappa }_0/T$ further suggests NaSn${}_2$As${}_2$ is an $s$-wave superconductor.

arXiv comment6 pages, 4 figures, submitted on 28 May

Cited by in corpus (1)

• Evidence for s-wave Pairing with Atomic Scale Disorder in the van der Waals Superconductor NaSn2As2