title: Out-of-plane temperature-dependent resistivity studies on Tl-based superconductors.
abstract: Temperature-dependent resistivities in the ab-plane and c-axis of Tl-based cuprates have been measured. Unlike the ab-plane properties, which are metallic, c-axis transport is semiconductor-like in the normal state for Tl(2)Ba(2)Ca(2)Cu(3)O(x) (Tl-2223) and Tl(2)Ba(2)CaCu(2)O(x) (Tl-2212). In contrast, for Tl(2)Ba(2)CuO(x) (Tl-2201), transport is metal-like in both the in-plane and the c-axis. For multi-layered cuprates, transport properties along the c-axis could be described by a tunnelling model, whereas for single-layered compound Tl-2201 it would be easier for the out-of-plane transport behaviour to be coherent since the there are no insulating Ca layers in its structure. Moreover, combining the studies on Bi-2201, which has an insulating behaviour for the out-of-plane resistivity, we suggest that the Tl-O layers in Tl-based superconductors could be conducting, unlike the weakly correlated Bi-O layers in Bi-based cuprates.
authors.affiliation: Tianjin Key Laboratory for Functional Materials and Device Physics, School of Material Science and Engineering, Tianjin University of Technology, Tianjin 300191, People's Republic of China. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, People's Republic of China.
authors.forename: Y C
authors.initials: YC
authors.lastname: Ma
authors.forename: J W
authors.initials: JW
authors.lastname: Liu
authors.forename: H W
authors.initials: HW
authors.lastname: Lu
authors.forename: H L
authors.initials: HL
authors.lastname: Zheng