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M: Metallphysik
M 33: Postersitzung
M 33.39: Poster
Thursday, March 29, 2001, 15:15–19:00, Foyer S4, CCH
The Σ 13 Twin Boundary in α-Al2O3: Energetics, Structure and Segregation of Cation Impurities — •Stefano Fabris and Christian Elsässer — Max-Planck-Institut für Metallforschung, Seestrasse 92, D-70174 Stuttgart, Germany
The atomistic structure of the Σ 13 ( 1014)[1210] symmetrical tilt grain boundary in α-Al2O3 was studied by combining several theoretical approaches: empirical shell-model potentials, semi-empirical tight-binding models, and first principles local-density-functional theory with a mixed-basis pseudopotential method. Results for the relative energetics of different boundary geometries as function of the axial grain separation are presented. Stable configurations with respect to intergranular cleavage are identified. Their local electronic structure and bonding are analysed. The influence of segregated cation impurities on the interfacial structure and energetics is also investigated.