title: Phase Separation from Electron Confinement at Oxide Interfaces.
abstract: Oxide heterostructures are of great interest for both fundamental and applicative reasons. In particular, the two-dimensional electron gas at the LaAlO_{3}/SrTiO_{3} or LaTiO_{3}/SrTiO_{3} interfaces displays many different properties and functionalities. However, there are clear experimental indications that the interface electronic state is strongly inhomogeneous and therefore it is crucial to investigate possible intrinsic mechanisms underlying this inhomogeneity. Here, the electrostatic potential confining the electron gas at the interface is calculated self-consistently, finding that such confinement may induce phase separation, to avoid a thermodynamically unstable state with a negative compressibility. This provides a robust mechanism for the inhomogeneous character of these interfaces.
authors.affiliation: Dipartimento di Fisica, Università di Roma "Sapienza", Piazzale Aldo Moro 5, 00185 Roma, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Scopigno
authors.affiliation: Dipartimento di Fisica, Università di Roma "Sapienza", Piazzale Aldo Moro 5, 00185 Roma, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Bucheli
authors.affiliation: Dipartimento di Fisica, Università di Roma "Sapienza", Piazzale Aldo Moro 5, 00185 Roma, Italy.|ISC-CNR and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Unità di Roma "Sapienza"
authors.forename: S
authors.initials: S
authors.lastname: Caprara
authors.affiliation: Laboratoire de Physique et d'Étude des Matériaux, CNRS-ESPCI ParisTech-UPMC, PSL Research University, 10 Rue Vauquelin, 75005 Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Biscaras
authors.affiliation: Laboratoire de Physique et d'Étude des Matériaux, CNRS-ESPCI ParisTech-UPMC, PSL Research University, 10 Rue Vauquelin, 75005 Paris, France.
authors.forename: N
authors.initials: N
authors.lastname: Bergeal
authors.affiliation: Laboratoire de Physique et d'Étude des Matériaux, CNRS-ESPCI ParisTech-UPMC, PSL Research University, 10 Rue Vauquelin, 75005 Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Lesueur
authors.affiliation: Dipartimento di Fisica, Università di Roma "Sapienza", Piazzale Aldo Moro 5, 00185 Roma, Italy.|ISC-CNR and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Unità di Roma "Sapienza"
authors.forename: M
authors.initials: M
authors.lastname: Grilli