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Geometry of {001} Surfaces of Spinel (MgAl 2 O 4 ): First‐Principles Simulations and Experimental Measurements
Author(s) -
Van Der Laag N. J.,
Fang C. M.,
De With G.,
De Wijs G. A.,
Brongersma H. H.
Publication year - 2005
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2005.00315.x
Subject(s) - spinel , density functional theory , materials science , surface reconstruction , surface (topology) , relaxation (psychology) , scattering , surface energy , ion , geometry , chemistry , computational chemistry , optics , metallurgy , physics , composite material , psychology , social psychology , mathematics , organic chemistry
The geometry of {001} surfaces of spinel (MgAl 2 O 4 ) was investigated by first‐principles simulations within density‐functional theory (DFT). The calculations show that the structure relaxation or reconstruction occurs for a depth of about 0.5 nm. The (001)‐Mg surface shows moderate relaxations and the (001)‐Al surface shows reconstruction: a new surface was formed with half of the subsurface oxygen atoms moved to the top. The surface energy was calculated to be about 1.7 J/m 2 for the relaxed (001)‐Mg surface and about 3.0 J/m 2 for the relaxed (001)‐Al surface.The chemical composition of a freshly fractured (001) surface of a spinel single crystal was measured using Low Energy Ion Scattering. The measured Al/Mg ratio indicates that the (001)‐Mg surface is more stable, in good agreement with the calculations.