Superconductivity in hydrated Li_x(H₂O)_yTaS₂

We have systematically studied the superconductivity in hydrated Li_x(H₂O)_0.86TaS₂ solid solution which is prepared for different lithium contents. The powder X-ray diffraction (PXRD) patterns suggest that all the samples are single-phase compounds, and the crystal structure is similar to that of 2H-TaS₂ (P6₃/mmc). Our transport measurements show a metallic behavior in the normal state and a transition to superconductivity at low temperatures for all involved Li_x(H₂O)_0.86TaS₂ samples. The superconducting transition temperature shows a dome-like dependence on the lithium intercalation content, with a maximum T_c of 4.6 K for x ≈ 0.42. Both the specific heat and the large superconducting shielding fraction reveal the bulk nature of superconductivity. The parameters extracted from specific-heat data are consistent with the T_c dependence on lithium content and suggest that superconductivity of hydrated Li_x(H₂O)_0.86TaS₂ is related to phonon softening and electron doping.