title: Wurtzite-type CoO nanocrystals in ultrathin ZnCoO films.
abstract: Surface x-ray diffraction experiments reveal that, in cobalt-doped ZnO films two to five monolayers thick, Wurtzite-type CoO nanocrystals are coherently embedded within a hexagonal boron-nitride- (h-BN)-type ZnO matrix, supporting the model of a phase separation. First-principles calculations confirm that, in contrast with ZnO, the formation of h-BN-type CoO is unfavorable in the ultrathin film limit. Our results are important for understanding magnetic properties of transition metal-doped semiconductors in general.
authors.affiliation: Max-Planck-Institut für Mikrostrukturphysik, D-06120 Halle, Germany.
authors.forename: H L
authors.initials: HL
authors.lastname: Meyerheim
authors.forename: C
authors.initials: C
authors.lastname: Tusche
authors.forename: A
authors.initials: A
authors.lastname: Ernst
authors.forename: S
authors.initials: S
authors.lastname: Ostanin
authors.forename: I V
authors.initials: IV
authors.lastname: Maznichenko
authors.forename: K
authors.initials: K
authors.lastname: Mohseni
authors.forename: N
authors.initials: N
authors.lastname: Jedrecy
authors.forename: J
authors.initials: J
authors.lastname: Zegenhagen
authors.forename: J
authors.initials: J
authors.lastname: Roy
authors.forename: I
authors.initials: I
authors.lastname: Mertig
authors.forename: J
authors.initials: J
authors.lastname: Kirschner