Superconducting interface in cuprate p-n heterostructures

In this explorative work, we combined two kinds of non-superconducting cuprates : over-doped ${\rm Pr}_{2-x}{\rm Ce}_x{\rm CuO}_4$ and under-doped ${\rm La}_{2-x}{\rm Sr} _x{\rm CuO}_4$ in the same p-n heterostructures in order to generate new behaviors through the interplay between the two materials. We will show that a thin superconducting layer ($<10$ nm) arise at the interface between these two compounds. We will discuss its actual location, its unexpected occurrence and its origin which is partly compatible with a charge transfer scenario that takes place in similar p-p cuprate heterostructures [1,2].\\[4pt] [1] A. Gozar \textit{et al.}, Nature 456, 782 (2008)\\[0pt] [2] G. Logvenov \textit{et al.}, Science 326, 699 (2009)