Superconductivity in a misfit compound (PbSe)1.12(TaSe2). (2nd November 2018)

• Record Type: Journal Article
• Authors: Yang, Xiaohui; Wang, Mengmeng; Li, Yupeng; Bai, Hua; Ma, Jiang; Sun, Xikang; Tao, Qian; Dong, Cheng; Xu, Zhu-An
• Is Part Of: Superconductor science & technology. Volume 31:Number 12(2018:Dec.)
• Publication Date: 2018-11-02
• Subjects: misfit chalcogenide -- weak coupling BCS superconductor -- charge carrier density -- anisotropic superconductivity; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/1361-6668/aae7b6
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: We report the discovery of superconductivity with a maximum T c ≈ 1.28 K in Br-doped (PbSe)1.12 (TaSe2 ), which is a new misfit compound consisting of alternating layers of distorted rocksalt PbSe and dichalcogenide TaSe2 . It is found that the Br-doping is required for the formation of this misfit compound and superconductivity can be tuned by the Br content. The large anisotropic parameter of resistivity γ ρ = ρ c / ρ ab ≈ 100 and that of the upper critical field γ H c 2 = H c 2 ab / H c 2 c ≈ 10 are obtained. The estimated c -axis coherence length ξ c ≈ 6.3 nm, larger than the c -axis lattice constant, which implies that this compound is an anisotropic three-dimensional superconductor. The Hall coefficient measurements suggest that the charge transport is dominated by the hole-type charge carrier and there is a charge transfer from the PbSe layer to the conducting TaSe2 layer. The small normalized specific heat jump Δ C / γ T c = 1.16 and electron–phonon coupling constant λ ep ≈ 0.61 indicate that Br-doped (PbSe)1.12 (TaSe2 ) is a weak coupling Bardeen–Cooper–Schrieffer superconductor.