Superconductivity in the orthorhombic phase of thermoelectric CsPbxBi4−xTe6 with 0.3≤x≤1.0

• Published in: Journal of solid state chemistry 2015-12, Vol.232, p.50-55
• Main Authors: Zhang, R.X., Yang, H.X., Tian, H.F., Chen, G.F., Wu, S.L., Wei, L.L., Li, J.Q.
• Format: Article
• Language: English
• Subjects: Compositional modulation; Superconductivity; Transmission electron microscopy
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2015.08.050

Experimental measurements clearly reveal the presence of bulk superconductivity in the CsPbxBi4−xTe6 (0.3≤x≤1.0) materials, i.e. the first member of the thermoelectric series of Cs[PbmBi3Te5+m], these materials have the layered orthorhombic structure containing infinite anionic [PbBi3Te6]− slabs separated with Cs+ cations. Temperature dependences of electrical resistivity, magnetic susceptibility, and specific heat have consistently demonstrated that the superconducting transition in Cs0.96Pb0.25Bi3.75Te6.04 occurs at Tc=3.1K, with a superconducting volume fraction close to 100% at 1.8K. Structural study using aberration-corrected STEM/TEM reveals a rich variety of microstructural phenomena in correlation with the Pb-ordering and chemical inhomogeneity. The superconducting material Cs0.96Pb0.25Bi3.75Te6.04 with the highest Tc shows a clear ordered structure with a modulation wave vector of q≈a*/2+c*/1.35 on the a–c plane. Our study evidently demonstrates that superconductivity deriving upon doping of narrow-gap semiconductor is a viable approach for exploration of novel superconductors. Bulk superconductivity is discovered in the orthorhombic Cs0.96Pb0.22Bi3.80Te6.02 materials with the superconducting transition Tc=3.1K. The compound shows a clear ordered structure with a modulation wave vector of q≈a*/2+c*/1.35 on the a–c plane. [Display omitted] •Bulk superconductivity is discovered in the orthorhombic CsPbxBi4−xTe6 materials.•The superconducting transition in Cs0.96Pb0.22Bi3.80Te6.02 occurs at Tc=3.1K.•Physical property measurements concerning the bulk superconductivity were present.•Structural modulation due to Pb-ordering was observed.