Anomalous enhancement of the superconducting transition temperature of electron-doped La 2 − x Ce x CuO 4 and Pr 2 − x Ce x CuO 4 cuprate heterostructures

The superconducting transition temperature T{sub c} of multilayers of electron-doped cuprates, composed of underdoped (or undoped) and overdoped La{sub 2-x}Ce{sub x}CuO{sub 4} (LCCO) and Pr{sub 2-x}Ce{sub x}CuO{sub 4} (PCCO) thin films, is found to increase significantly with respect to the T{sub c} of the corresponding single-phase films. By investigating the critical current density of superlattices with different doping levels and layer thicknesses, we find that the T{sub c} enhancement is caused by a redistribution of charge over an anomalously large distance.