title: High-T(c) Superconductivity at the Interface between the CaCuO2 and SrTiO3 Insulating Oxides.
abstract: At interfaces between complex oxides it is possible to generate electronic systems with unusual electronic properties, which are not present in the isolated oxides. One important example is the appearance of superconductivity at the interface between insulating oxides, although, until now, with very low T(c). We report the occurrence of high T(c) superconductivity in the bilayer CaCuO(2)/SrTiO(3), where both the constituent oxides are insulating. In order to obtain a superconducting state, the CaCuO(2)/SrTiO(3) interface must be realized between the Ca plane of CaCuO(2) and the TiO(2) plane of SrTiO(3). Only in this case can oxygen ions be incorporated in the interface Ca plane, acting as apical oxygen for Cu and providing holes to the CuO(2) planes. A detailed hole doping spatial profile can be obtained by scanning transmission electron microscopy and electron-energy-loss spectroscopy at the O K edge, clearly showing that the (super)conductivity is confined to about 1-2 CaCuO(2) unit cells close to the interface with SrTiO(3). The results obtained for the CaCuO(2)/SrTiO(3) interface can be extended to multilayered high T(c) cuprates, contributing to explaining the dependence of T(c) on the number of CuO(2) planes in these systems.
authors.affiliation: Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy.|CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Di Castro
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6116, USA.
authors.forename: C
authors.initials: C
authors.lastname: Cantoni
authors.affiliation: Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Ridolfi
authors.affiliation: CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Aruta
authors.affiliation: Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy.|CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Tebano
authors.affiliation: CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy.|Facoltà di Ingegneria, Università degli studi Niccolò Cusano, Rome I-00166, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Yang
authors.affiliation: Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy.|CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Balestrino