Volume 123, Number 4, August 2018
|Number of page(s)||6|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||18 September 2018|
Nodeless superconductivity in the SnAs-based van der Waals-type superconductor NaSn2As2
1 State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University - Shanghai 200433, China
2 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, School of Physical Sciences, University of Chinese Academy of Sciences - Beijing 100190, China
3 Collaborative Innovation Center of Advanced Microstructures - Nanjing 210093, China
Received: 25 May 2018
Accepted: 26 August 2018
We grew the single crystals of the SnAs-based van der Waals (vdW)-type superconductor NaSn2As2 and systematically measured its resistivity, specific heat, and ultralow-temperature thermal conductivity. The superconducting transition temperature 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 further suggests NaSn2As2 is an s-wave superconductor.
PACS: 74.25.Bt – Thermodynamic properties / 74.25.F- – Transport properties / 74.25.-q – Properties of superconductors
© EPLA, 2018
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