Using polarity for engineering oxide nanostructures: structural phase diagram in free and supported MgO(111) ultrathin films.
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.
Goniakowski
Jacek
J
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
Noguera
Claudine
C
Giordano
Livia
L