TY - JOUR
T1 - Heteroepitaxial growth of MgO(111) thin films on Al 2O 3(0001)
T2 - Evidence of a wurtzite to rocksalt transformation
AU - Martínez-Boubeta, Carlos
AU - Botana, Antía S.
AU - Pardo, Victor
AU - Baldomir, Daniel
AU - Antony, Aldrin
AU - Bertomeu, Joan
AU - Rebled, Josep M.
AU - López-Conesa, Lluís
AU - Estradé, Sonia
AU - Peiró, Francesca
PY - 2012/7/19
Y1 - 2012/7/19
N2 - 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.
AB - 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.
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U2 - 10.1103/PhysRevB.86.041407
DO - 10.1103/PhysRevB.86.041407
M3 - Article
AN - SCOPUS:84864625054
SN - 1098-0121
VL - 86
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 4
M1 - 041407
ER -