Synthesis and Superconducting Properties NaSn2As2

We report a combined theoretical and experimental investigation of high-quality monocrystalline samples of the stoichiometric NaSn2As2 superconductor. Transport properties are measured over the temperature range from 300 to 0.01 K with applied magnetic fields up to 0.5 T. Analysis of the critical current density temperature dependences Jc(T) and the upper critical field Hc2(T) yields an estimate of the Ginzburg‒Landau parameter κ ≈ 35, unambiguously classifying NaSn2As2 as a type-II superconductor. Ab initio calculations of the superconducting properties of NaSn2As2, performed using density functional theory, confirm the electron‒phonon nature of superconductivity.