Superconductivity in a Misfit Layered (SnS)1.15 (TaS2) Compound
R. Sankar*, G. Peramaiyan, I. P. Muthuselvam, C.-Y. Wen, X. Xu, and F. C. Chou*
2018/03/01
We report the single crystal growth and superconducting properties of a misfit layered (SnS)1.15(TaS2) compound. The transport, magnetic, and thermodynamic properties revealed the superconducting transition with an onset temperature of Tc ∼ 3.01 K. The high resolution transmission electron microscopy (HRTEM) image clearly shows the misfit stacking of SnS and TaS2 layers. Based on the Werthamer–Helfand–Hohenberg (WHH) formula and Ginzburg–Landau theory, the upper critical fields are Hc2(0) = 0.64 ± 0.06 T and 0.22 ± 0.02 T with coherence lengths of ξ = 22.67 and 38.68 nm for field applied perpendicular (H⊥) and parallel (H//) to the plane, respectively. On the basis of the specific heat measurement data analysis of derived parameters including Sommerfeld coefficient γ = 5.831 ± 0.012 mJ mol–1 K–2, Debye temperature ΘD = 151 K, specific heat jump ΔCe/γTc = 0.812, and electron–phonon coupling constant λel–ph ∼ 0.724, all indicate the weak-coupling nature for (SnS)1.15(TaS2) as a misfit layered superconductor. Resistivity measurements show that Tc increases from temperature 3.01 to 3.85 K at 1.95 GPa, and linear dependence of Tc as a function of pressure (P) is observed up to 1.583 GPa.
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