Superconducting properties of [BaCuOx](2)/[CaCuO2](n) artificial structures with ultrathick CaCuO2 blocks

Article

关键词: HIGH-TEMPERATURE SUPERCONDUCTORS;    INSULATOR TRANSITION;    SINGLE-CRYSTALS;    FILMS;    SUPERLATTICES;    LOCALIZATION;    TRANSPORT;    DISORDER;   

DOI  :  10.1103/PhysRevB.62.9835

来源: SCIE

【 摘 要 】

The electrical transport properties of [BaCuOx](2) /[CaCuO2](n)(CBCCO-2 X n) underdoped high-temperature superconducting superlattices grown by pulsed laser deposition have been investigated. Starting from the optimally doped CBCCO-2 X 2 superlattice, having three CuO2 planes and T-c around 80 K, we have systematically increased the number n up to 15 moving toward the underdoped region and hence decreasing T-c. For n > 11 the artificial structures are no longer superconducting, as expected, for a uniformly distributed charge carrier density inside the conducting block layer. The sheet resistance of such artificial structures (n approximate to 11) turns out to be quite temperature independent and close to the two-dimensional quantum resistance 26 k Omega. A further increase of the number of CuO2 planes results in an insulator-type dependence of R(T) in the wide range of temperatures from room temperature to 1 K. The value of the sheet resistance separating the superconducting and the insulating regimes supports the fermionic scenario of the superconductor-insulator transition in these systems.

【 授权许可】

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