Superconductivity in hydrated Lix(H2O)yTaS2. Issue 10 (22nd February 2023)

• Record Type: Journal Article
• Authors: Liu, Huanlong; Huangfu, Shangxiong; Lin, Hai; Zhang, Xiaofu; Schilling, Andreas
• Is Part Of: Journal of materials chemistry. Volume 11:Issue 10(2023)
• Page Start: 3553
• Page End: 3561
• Publication Date: 2023-02-22
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2tc04353j
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : We have studied the structural and physical properties of the superconducting hydrated Li x (H2 O) y TaS2 (0.22 ≤ x ≤ 0.58, y ≈ 0.86). The transition temperature shows a dome-shape dependence on the Li content with a maximum T c of 4.6 K for x ≈ 0.42. Abstract : We have systematically studied the structural and physical properties of the superconducting hydrated Li x (H2 O) y TaS2 (0.22 ≤ x ≤ 0.58, y ≈ 0.86). The powder X-ray diffraction patterns suggest that all the samples are single-phase compounds, and the crystal structure is similar to that of 2 H -TaS2 ( P 63 / mmc ). The transition temperature to superconductivity shows a dome-shape dependence on the lithium content x with a maximum T c of 4.6 K for x ≈ 0.42, which is larger than in corresponding optimally doped 2 H -TaS2 superconductors without water or organic intercalants ( T c ∼ 4.2 K). There are no signs of a charge-density-wave formation in hydrated Li x (H2 O) y TaS2 . While our magnetic data indicate a rather strongly type-II behavior, heat-capacity measurements reveal, like in other 2 H -TaS2 -type compounds, a reduced discontinuity Δ C e / γT c ≈ 0.8 at T c, which is smaller than the standard BCS value 1.43. From the corresponding Sommerfeld constants γ and Debye temperatures Θ D we can derive the parameter describing the electron–phonon coupling λ ep and the electron density of states DOS( E F ) at the Fermi level as functions of x . While the variation of the DOS( E F ) is consistent with that of T c, indicating that the lithium intercalation is tuning T c via changing the DOS( E F ) in 2 H -Li x (H2 O) y TaS2, the simultaneous changes of λ ep and Θ D may also play a certain role.