Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 2: Superconductivity: Properties and Electronic Structure 1
TT 2.9: Vortrag
Montag, 20. März 2017, 12:00–12:15, HSZ 103
Superconductivity in TaSnS2 — •Manuel Feig1,2, Matej Bobnar2, Walter Schnelle2, Igor Veremchuk2, Sergiy Medvediev2, Andreas Leithe-Jasper2, and Roman Gumeniuk1,2 — 1Institut für Experimentelle Physik, TU Bergakademie Freiberg, Leipziger Str. 23, 09596 Freiberg, Germany — 2MPI für Chemische Physik fester Stoffe, Nöthnitzer Str. 40, 01187 Dresden, Germany
The hexagonal TaSnS2 sulphide is reported to be a superconductor with Tc = 2.8 K [1]. However, its superconducting parameters have not been studied up to now. The powder of TaSnS2 was compacted by spark plasma sintering (SPS). The measurements of magnetic susceptibility revealed a superconducting transition at Tc = 2.9 K in agreement with earlier report [1]. The measurements of electrical resistivity and specific heat showed different critical magnetic fields µ0Hc2 = 22 mT and 200 mT, respectively. This contradiction can indicate an anisotropy of superconducting properties caused by 2H-structure of TaSnS2. The specific heat jump at the transition Δcp/γTc = 0.9 and the energy gap ratio Δ(0)/kBTc = 1.17 are well below the values (e.g. 1.43 and 1.76) predicted by BCS theory. This can be again due to an anisotropy of properties or/and by a multigap type of superconductivity. To finally shed light on the superconducting mechanisms in TaSnS2 measurements on oriented crystals are required. High pressure measurements revealed that Tc for TaSnS2 becomes zero for p > 2.5 GPa. The Raman measurements indicated a structural phase transition for TaSnS2 above 7 GPa.
[1] J. Dijkastra et al., Phys. Rev. B 40 (1989) 12111.