Heteroepitaxial growth of MgO(111) thin films on Al 2O 3(0001): Evidence of a wurtzite to rocksalt transformation

Carlos Martínez-Boubeta, Antía S. Botana, Victor Pardo, Daniel Baldomir, Aldrin Antony, Joan Bertomeu, Josep M. Rebled, Lluís López-Conesa, Sonia Estradé, Francesca Peiró

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

We report on a growth study of MgO films deposited on Al 2O 3(0001) substrates by magnetron sputtering. The films exhibited a preferred rocksalt MgO(111) orientation. Surprisingly, depending on the O 2 gas flow ratio, a structure of graphiticlike wurtzite MgO(0001) has been revealed. The observed Mg-O perpendicular bond length reduction is accompanied by an atomically flat surface morphology for the development of MgO(111) films; the transition to the bulk rocksalt structure occurs in the 3-6 nm coverage range. Previously, relaxation of the electrostatic instability of MgO(111) films accompanied by an in-plane lattice increase has been suggested theoretically. Here, relying on ab initio calculations, we infer that Mg vacancies facilitate the lattice match with the substrate. This mechanism suggests methods to engineer oxide heterostructures.

Original languageEnglish (US)
Article number041407
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume86
Issue number4
DOIs
StatePublished - Jul 19 2012
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Heteroepitaxial growth of MgO(111) thin films on Al <sub>2</sub>O <sub>3</sub>(0001): Evidence of a wurtzite to rocksalt transformation'. Together they form a unique fingerprint.

  • Cite this

    Martínez-Boubeta, C., Botana, A. S., Pardo, V., Baldomir, D., Antony, A., Bertomeu, J., Rebled, J. M., López-Conesa, L., Estradé, S., & Peiró, F. (2012). Heteroepitaxial growth of MgO(111) thin films on Al 2O 3(0001): Evidence of a wurtzite to rocksalt transformation. Physical Review B - Condensed Matter and Materials Physics, 86(4), [041407]. https://doi.org/10.1103/PhysRevB.86.041407