Role of impurity oxygen in superconductivity of "non-doped" T'-(La,RE)2CuO4

Abstract

We have systematically investigated the effect of oxygen nonstoichiometry in a nominally undoped superconductor T'-(La,Y)2CuO4+y. In the experiments, the reduction condition was changed after the sample growth by MBE. The superconductivity is very sensitive to the reduction condition. With systematically increasingly reduced atmospheres, resistivity shows a continuous drop and no discontinuity is observed even until the appearance of superconductivity. The absence of the highly insulating state expected for Mott insulators around y ~ 0 suggests that T'-(La,Y)2CuO4 has intrinsic carriers. The role of residual apical oxygen, which is detrimental to superconductivity, is also discussed based on the resistivity-temperature characteristics in insufficiently reduced samples.

proceedings of ISS 2004

References in corpus (4)

• New class of T-prime-structure cuprate superconductors
• Kondo effect in underdoped n-type superconductors
• Effect of a magnetic field on the long-range magnetic order in insulating Nd2CuO4, nonsuperconducting and superconducting Nd1.85Ce0.15CuO4
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Cited by in corpus (10)

• Generic phase diagram of "electron-doped" T' cuprates
• Superconductivity in undoped T' cuprates with Tc over 30 K
• Superconductivity in undoped T'-RE2CuO4 with Tc over 30 K
• New superconduting cuprates with no effective doping: T'-(La3+)2-x(RE3+)xCuO4
• Electronic Structure of Ce-Doped and -Undoped Nd${}_2$CuO${}_4$ Superconducting Thin Films Studied by Hard X-ray Photoemission and Soft X-ray Absorption Spectroscopy
• Extended superconducting dome of electron-doped cuprates after protect annealing revealed by ARPES
• Charge transfer gap for T'-RE2CuO4 and T-La2CuO4 as estimated from Madelung potential calculations
• Superconductivity induced by structural reorganization in the electron-doped cuprate Nd${}_{2-x}$Ce${}_x$CuO${}_4$
• Origin of superconductivity in nominally "undoped" T'-La${}_{2-x}$Y${}_x$CuO${}_4$ films
• Inhomogeneous reduction-annealing effects on the electron-doped cuprate superconductor revealed by micro-focused angle-resolved photoemission spectroscopy