Emergence of high-temperature superconductivity at the interface of two Mott insulators

Interfacial superconductivity has manifested itself in various types of heterostructures: band insulator-band insulator, insulator-Mott and Mott insulator-metal. We report the observation high-temperature (HTS) a complementary long expected type heterostructures, which consists two insulators, La2CuO4 (LCO) PrBa2Cu3O7 (PBCO). By carefully controlling oxidization condition selectively doping CuO2 planes with Fe atoms, suppress superconductivity, we found that arises at LCO side is confined within no more than unit cells (about 2.6 nm) near interface. A phenomenon overcome barrier will show up if excess oxygen present during growth. Some possible mechanisms for interfacial HTS have been discussed, attribute it to redistribution oxygen.