title: Using polarity for engineering oxide nanostructures: structural phase diagram in free and supported MgO(111) ultrathin films.
abstract: Using an ab initio total energy approach, we study the stability of free and Ag(111)-supported MgO(111) ultrathin films. We unravel a novel microscopic mechanism of stabilization of polar oxide orientations, based on a strong modification of the MgO structural phase diagram with respect to the bulk material. We predict that, at low thickness, films which are either unsupported or deposited on Ag(111) display a graphitelike Bk structure rather than the expected rocksalt one. Our results provide a consistent interpretation of recent experimental findings, exemplify the efficiency of this novel stabilization mechanism, and suggest new methods to engineer oxide nanostructures.
authors.affiliation: Groupe de Physique des Solides, UMR 7588 CNRS, Universités Paris 6-Paris 7, Campus de Boucicaut, 140 rue de Lourmel, 75015 Paris, France. jacek@gps.jussieu.fr
authors.forename: Jacek
authors.initials: J
authors.lastname: Goniakowski
authors.forename: Claudine
authors.initials: C
authors.lastname: Noguera
authors.forename: Livia
authors.initials: L
authors.lastname: Giordano