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

Abstract

The recent discovery of superconductivity in NaSn${}_2$As${}_2$ with a van der Waals layered structure raises immediate questions on its pairing mechanism and underlying electronic structure. Here, we present measurements of the temperature-dependent magnetic penetration depth $\lambda (T)$ in single crystals of NaSn${}_2$As${}_2$ down to $\sim 40$ mK. We find a very long penetration depth $\lambda (0)=960$ nm, which is strongly enhanced from the estimate of first-principles calculations. This enhancement comes from a short mean free path $\ell \approx 1.7$ nm, indicating atomic scale disorder possibly associated with the valence-skipping states of Sn. The temperature dependence of superfluid density is fully consistent with the conventional fully gapped s-wave state in the dirty limit. These results suggest that NaSn${}_2$As${}_2$ is an ideal material to study quantum phase fluctuations in strongly disordered superconductors with its controllable dimensionality.

arXiv comment6 pages, 4 figures. Accepted as a Rapid Communication in Physical Review B

References in corpus (25)

• BoltzTraP. A code for calculating band-structure dependent quantities
• Heavy fermion superconductivity and magnetic order in non-centrosymmetric $CeP{t}_{3}Si$
• Superconductivity in Weyl Semimetal Candidate MoTe2
• Superconductivity in the Intercalated Graphite Compounds C6Yb and C6Ca
• Pressure-driven dome-shaped superconductivity and electronic structural evolution in tungsten ditelluride
• Localization of preformed Cooper-pairs in disordered superconductors
• Nature of the superconductor-insulator transition in disordered superconductors
• Superconductivity emerging from suppressed large magnetoresistant state in WTe2
• 3D Dirac semimetals: current materials, design principles and predictions of new materials
• Meissner - London state in superconductors of rectangular cross-section in perpendicular magnetic field
• Phase diagram of a strongly disordered s-wave superconductor, NbN, close to the metal-insulator transition
• Disorder-induced topological change of the superconducting gap structure in iron pnictides
• Effects of Neutron Irradiation on Pinning Force Scaling in State-of-the-Art Nb3Sn Wires
• Nodeless vs nodal order parameters in LiFeAs and LiFeP superconductors
• Absence of non-linear Meissner effect in YBa2Cu3O6.95
• NaSn2As2: An Exfoliatable Layered van der Waals Zintl Phase
• Superfluid density and carrier concentration across a superconducting dome: the case of SrTi${}_{1-x}$Nb${}_x$O${}_3$
• SnAs-based layered superconductor NaSn2As2
• Full-gap superconductivity robust against disorder in heavy-fermion CeCu2Si2
• Anomalous metallic state above the upper critical field of the conventional three-dimensional superconductor AgSnSe2 with strong intrinsic disorder
• Using electron irradiation to probe iron - based superconductors
• Evolution of the superconducting energy gap structure concomitant with Fermi surface reconstruction in the heavy-fermion superconductor CeCoIn5
• Rutgers relation for the analysis of superfluid density in superconductors
• Nodeless superconductivity in the SnAs-based van der Waals type superconductor NaSn2As2
• Na1-xSn2P2 as a new member of van der Waals-type layered tin pnictide superconductors

Cited by in corpus (7)

• Tuning the Parity Mixing of Singlet-Septet Pairing in a Half-Heusler Superconductor
• Prediction of Tunable Spin-Orbit Gapped Materials for Dark Matter Detection
• Electronic structure and superconductivity of the non-centrosymmetric Sn${}_4$As${}_3$
• Axis-dependent carrier polarity in polycrystalline NaSn${}_2$As${}_2$
• Anisotropic Scattering in Goniopolar Metal NaSn${}_2$As${}_2$
• Enhanced superconductivity by Na doping in SnAs-based layered compound Na${}_{1+x}$Sn${}_{2-x}$As${}_2$
• Superconductivity in layered Zintl phase LiSn2As2