Unconventional transport and superconducting properties in electron-doped cuprates

Abstract

We report a study of transport and magnetic properties of high-quality c axis-oriented superconducting T′-RE2−xCexCuO4 (RE = La, Pr, Nd) thin films grown by molecular beam epitaxy at optimal as well as x = 0.00 doping levels. While the superconducting coherence length ξGL decreases from RE = Nd to La, it remains nearly constant as a function of doping. For optimally doped T′-cuprates, the electronic conductivity is higher than the dopant-free sample, while Tc is higher for the dopant-free samples for RE = Nd and Pr. We estimated the superconducting penetration depth λab by using a relationship obtained from optical measurements and compared it to the diamagnetic response, which corresponds to the superfluid density ns. Our data suggest that electron doping increases the superfluid density ns significantly, but the pairing interaction is not affected. In the normal state, the temperature dependence of the resistivity was used to deduce the Fermi temperature TF, from which we estimated the charge-carrier concentration n. A systematic relationship between n, ns, and the superconducting transition temperature Tc was not observed. We finally conclude that the superconducting ground state is merely influenced by Ce doping with respect to Tc and ξGL but solely by the RE element.

Source-reported materials — not catalogue approval

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