Ab initio study of gamma-Al2O3 surfaces

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© 2004 American Physical Society (APS). This is the accepted version of the following article: Pinto, Henry P. & Nieminen, Risto M. & Elliott, Simon D. 2004. Ab initio study of gamma-Al2O3 surfaces. Physical Review B. Volume 70, Issue 12. 125402/1-11. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.70.125402, which has been published in final form at http://journals.aps.org/prb/abstract/10.1103/PhysRevB.70.125402.

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Journal Title

Journal ISSN

Volume Title

School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2004

Major/Subject

Mcode

Degree programme

Language

en

Pages

125402/1-11

Series

Physical Review B, Volume 70, Issue 12

Abstract

Starting from the theoretical prediction of the γ−Al2O3 structure using density-functional theory in the generalized gradient approximation, we have studied the (1 1 1), (0 0 1), (1 1 0), and (1 5 0) surfaces. The surface energies and their corresponding structures are computed and compared with predictions for (0 0 0 1) α−Al2O3 and available experimental results for γ-alumina surfaces. (1 1 1) and (0 0 1) surfaces are predicted to be equally stable, but to show quite different structure and reactivity. Whereas a low coverage of highly reactive trigonal Al occurs on (1 1 1), (0 0 1) exhibits a more dense plane of both five-coordinate and tetrahedral Al. Microfaceting of a (1 1 0) surface into (1 1 1)-like planes is also observed. The implications for the structure of ultrathin dielectric films and for the surfaces of disordered transition aluminas are discussed.

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Keywords

surface energies, alumina

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Citation

Pinto, Henry P. & Nieminen, Risto M. & Elliott, Simon D. 2004. Ab initio study of gamma-Al2O3 surfaces. Physical Review B. Volume 70, Issue 12. 125402/1-11. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.70.125402.