Anomalous Enhancement of the Superconducting Transition Temperature in Electron-Doped Cuprate Heterostructures

Abstract

The superconducting transition temperature $T_c$ of multilayers of electron-doped cuprates, composed of underdoped (or undoped) and overdoped La% ${}_{2-x}$Ce${}_x$CuO${}_4$ (LCCO) and Pr${}_{2-x}$Ce${}_x$CuO${}_4$ (PCCO) thin films, is found to increase significantly with respect to the $T_c$ 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 $T_c$ enhancement is caused by a redistribution of charge over an anomalously large distance.

4 figures. To appear in PRB as a Rapid Communication