Superconductivity in a Misfit Layered (SnS)_1.15(TaS₂) Compound

Abstract

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 T c ∼ 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 H c2(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 Θ D = 151 K, specific heat jump ΔC e /γT c = 0.812, and electron–phonon coupling constant λ el–ph ∼ 0.724, all indicate the weak-coupling nature for (SnS)1.15(TaS2) as a misfit layered superconductor. Resistivity measurements show that T c increases from temperature 3.01 to 3.85 K at 1.95 GPa, and linear dependence of T c as a function of pressure (P) is observed up to 1.583 GPa.

Multi-band Superconductivity in a misfit layered compound (SnSe)1.16(NbSe2)2

“…These changes may be related to the change in the Fermi surface caused by the reduced charge transfer between the two subsystems. Furthermore, the normalized specific heat jump ΔC e /γT c is estimated to be 0.85, close to some other MLCs superconductors [2,13,14].…”

“…In the MLCs family, many superconductors have been discovered [1, 2, 3-6, 7-12, 13-15]. Their T c values are in the range of about 0.4-5.3 K. The upper critical field (H c2 ) of most MLC superconductors are usually small in both in-plane and out-of-plane directions, [8,2,13,[15][16][17][18], and only a few MLC superconductors exhibit unusually large H c2 [14,19].…”

Growth and anisotropy evaluation of NbBiCh3 (Ch = S, Se) misfit-layered superconducting single crystals

“…Misfit layered compounds (MLC) exhibit unique physical properties due to incommensurate layered structures [1]. The general chemical formula of these materials is represented as (MX) 1+δ (TX 2 ), where MX and TX 2 (M = Sn, Pb, Bi, Sb, rare earth elements; T = transition metal; X = S, Se, Te) are monochalcogenide and transition metal dichalcogenide layers, respectively [2][3][4]. In particular, the physical properties of the incommensurate direction have attracted much attention.…”

Superlattices based on van der Waals 2D materials

“…47 Superconductivity is another application barely explored yet in both misfit layer compounds and ferecrystals. Superconductivity in the synthesized misfit layer compounds (SnSe) 1.16 (NbSe 2 ) 51 and (SnS) 1.15 (TaS 2 ) 52 with critical temperatures (T c ) of, respectively, 3.4 and 3.01 K was recently reported. In the (PbSe) 1.14 (NbSe 2 ) n ferecrystal, 53 the shift of T c from 2.66 (n = 3), 1.91 (n = 2) and 1.11 (n = 1) K was observed.…”

“…Elements of the unit cell Modulation by (dimension) Applications (ref. ) Vertical stacking Chemical composition, lattice (mis)match (1D) IR photodetectors 15,16,20 Phase-change memory [28][29][30][31][32][33][34] Thermoelectrics [47][48][49][50] Superconductivity [51][52][53][54] Intercalated compounds Chemical composition, structuring, charge transfer (1D)…”