Title:
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Heteroepitaxial growth of MgO(111) thin films on Al2O3(0001): Evidence of a wurtzite to rocksalt transformation
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Author:
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Martínez Boubeta, José Carlos; Botana, Antía S.; Pardo, Víctor; Baldomir, Daniel; Antony, Aldrin; Bertomeu i Balagueró, Joan; Rebled, J. M. (José Manuel); López-Conesa, Lluís; Estradé Albiol, Sònia; Peiró Martínez, Francisca
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Other authors:
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Universitat de Barcelona |
Abstract:
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We report on a growth study of MgO films deposited on Al2O3(0001) substrates by magnetron sputtering. The films exhibited a preferred rocksalt MgO(111) orientation. Surprisingly, depending on the O2 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 [Phys. Rev. Lett. 98, 205701 (2007)]. 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. |
Subject(s):
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-Pel·lícules fines -Òxids metàl·lics -Cristal·lografia -Estructura electrònica -Superconductors -Optoelectrònica -Thin films -Metallic oxides -Crystallography -Electronic structure -Superconductors -Optoelectronics |
Rights:
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(c) American Physical Society, 2012
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Document type:
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Article Article - Published version |
Published by:
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American Physical Society
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